OPEC is the abbreviation for:

The correct answer is A, National Institution for Transforming India. NITI Aayog replaced the Planning Commission on 1 January 2015 and works as the policy think tank of the Government of India. The Prime Minister is its chairperson, and it has a vice-chairperson, a chief executive officer and the chief ministers of the states in its Governing Council. Option B is wrong because no official expansion uses the word Initiative, though it sounds plausible. Option C is wrong because the abbreviation has nothing to do with technology; NITI is a policy body, not a technical institute. Option D is wrong because industrial training institutes are the ITIs, a quite separate network of vocational schools run under the Directorate General of Training. Read every word of the expansion before marking, since the distractors differ by one word.

The correct answer is B, Light Amplification by Stimulated Emission of Radiation. A laser produces a narrow, coherent, single-wavelength beam by stimulated emission, in which an excited atom is made to release a photon identical to the one that strikes it. Option A is the usual trap, replacing Amplification with Absorption: absorption is the opposite process, in which energy is taken in rather than released as a beam. Option C is wrong because the word Linear belongs to no standard expansion, and lasers are not described as linear amplifiers of standard rays. Option D is wrong because a laser neither analyses light nor emits sequentially. The companion acronym is MASER, Microwave Amplification by Stimulated Emission of Radiation, which came first and was developed by Charles Townes.

The correct answer is C, Indian Financial System Code. The IFSC is an eleven-character alphanumeric code that identifies a particular bank branch in the electronic payment systems operated by the Reserve Bank of India, and it is required for NEFT and RTGS transfers. The first four characters are the bank, the fifth is zero, and the last six identify the branch. Option A is wrong because the word Settlement belongs to RTGS, Real Time Gross Settlement, not to the IFSC. Option B is wrong because the code is national, not international; it covers branches in India alone. Option D is wrong because there is no body called a fund settlement centre in the payment system. The companion abbreviation on a cheque leaf is MICR, Magnetic Ink Character Recognition.

The correct answer is B, United Nations Children's Fund. The agency was created by the General Assembly in 1946 as the United Nations International Children's Emergency Fund, for children in countries ruined by the Second World War, and in 1953 it was made a permanent part of the United Nations and renamed the United Nations Children's Fund, keeping the familiar acronym. Its headquarters is in New York, and it received the Nobel Peace Prize in 1965. Option A is the original name, which is why it is the hardest distractor; examiners who want it say "originally". Option C is wrong because education is the work of UNESCO, which is a separate agency based in Paris. Option D is wrong because no United Nations body is called a universal nations forum.

The correct answer is A, Radio Detection and Ranging. Radar sends out radio waves and measures the echo that returns from an object, so the time taken gives the distance, or range, and the shift in frequency gives the speed by the Doppler effect. The underwater equivalent is SONAR, Sound Navigation and Ranging, which uses sound waves because radio waves are absorbed quickly in water. Option B is wrong because no standard expansion uses Radial Direction. Option C is tempting since radar does depend on reflection, but the final word of the acronym is Ranging, which is the measurement of distance. Option D is wrong because Rapid and Reporting belong to no expansion of the term. Doppler weather radars are used by the India Meteorological Department to track rain and cyclones.