What is the approximate distance between two consecutive parallels of latitude?

The correct answer is C, about 111 kilometres. The circumference of the earth along a meridian is close to 40,000 kilometres, and dividing that by 360 degrees gives roughly 111 kilometres for one degree of latitude. Because the angle is measured at the centre of the earth, this figure holds almost everywhere from the equator to the poles.

Option A, 51 kilometres, and option B, 88 kilometres, are distances between meridians at high latitudes, since meridians draw closer together as they approach the poles; at the equator the gap between two meridians is also about 111 kilometres, and it falls to zero at the poles. Option D, 150 kilometres, has no basis. A useful related figure is that one minute of latitude equals one nautical mile, that is 1,852 metres, which is why sailors measure distance in nautical miles.