The correct choice is (b) 14
To explain I would say: In lettering ‘A’ type, the height of the capital letter is divided into 14 parts while in lettering ‘B’ type it is divided into 10 parts. The height of letters and numerals for engineering drawing can be selected from 2.5, 3.5, 5, 7, 10, 14 and 20 mm according to drawing size.