India's latitudinal and longitudinal extent measured in degrees are almost the same, but its north-south extent measured in km is greater than its east-west extent. This is due to the fact that
(a) longitudes are not parallel lines
(b) the distance between latitudes remains the same but the distance between longitudes is greatest at the Equator and nil at the poles where all longitudes join
(c) all longitudes with their opposites form great circles
(d) the earth is not a perfect sphere
