World Post Day is observed every year on

The correct answer is C, 15 August 1972. The six-digit Postal Index Number was brought into use on 15 August 1972 to replace the practice of writing out long postal addresses that often repeated place names found in several states. Option A is wrong because 15 August 1947 is the date of independence; the posts then still worked on the colonial system without numeric codes. Option B is wrong because no postal reform of this kind took place in 1965, and the date is offered only because it combines a Republic Day with a plausible year. Option D is wrong because 1986 is the year Speed Post was launched by the Department of Posts, a separate development that candidates often confuse with the PIN. Note also that the PIN shares its introduction date with Independence Day, which is how it is best remembered.

The correct answer is A, Shriram Bhikaji Velankar. He was an Additional Secretary in the Union Ministry of Communications and a Sanskrit scholar, and he worked out the six-digit code that came into use on 15 August 1972. Option B is wrong because Sir Bartle Frere was the Commissioner of Sind who issued the Scinde Dawk in 1852, the first adhesive postage stamp in Asia, more than a century earlier. Option C is wrong because Rowland Hill was the British reformer behind the penny post and the idea of prepaid uniform postage in Britain, and he had no part in the Indian PIN. Option D is wrong because Lord Dalhousie was the Governor-General under whom the Post Office Act of 1854 reorganised the Indian posts, which is a different reform altogether.

The correct answer is B, the postal region. The first of the six digits identifies one of the nine postal regions or zones into which the country is divided for the purpose of the PIN. Option A is wrong because the delivery post office is identified by the last three digits of the code, which are the most specific part of it. Option C is wrong because the sorting district is given by the third digit, read together with the first two; the first digit alone is far too broad for that. Option D is wrong because the zones are not arranged by the alphabetical order of state names at all; they run in a rough clockwise sweep beginning with the north-western states in zone 1, and the ninth zone is not a state grouping but the Army Postal Service.

The correct answer is C, the Army Postal Service. Zone 9 is the only one of the nine PIN zones that is functional rather than geographical: it covers Army Post Office and Field Post Office addresses wherever the units concerned are posted, so that mail to serving personnel need not disclose their location. Option A is wrong because the North-Eastern states fall in zone 7, along with West Bengal, Odisha and Sikkim. Option B is wrong because the Andaman and Nicobar Islands are also in zone 7 and not in a zone of their own. Option D is wrong because Jammu and Kashmir and Ladakh lie in zone 1 with Delhi, Haryana, Punjab, Himachal Pradesh and Chandigarh. Zone 9 is the detail most often tested in this topic.

The correct answer is B, Scinde Dawk. It was issued in 1852 in the province of Sind by Sir Bartle Frere, its Commissioner, and was the first adhesive postage stamp brought out anywhere in Asia. Option A is wrong because the Penny Black was the world's first adhesive postage stamp, issued in Britain in 1840, not in Asia. Option C is wrong because the Jai Hind stamp bearing the national flag was issued on 21 November 1947 and was the first commemorative stamp of independent India, almost a century later. Option D is wrong because the Queen Victoria stamps of 1854 were the first to be valid throughout India, but they came two years after the Scinde Dawk, which remains the earliest. The distinction between the all-India stamp of 1854 and the provincial stamp of 1852 is the trap here.