Explanation:
1 ft = 12 in.
so, 8 in = 8/12 = 2/3 ft
therefore, 11 ft 8 in = 11.66666666... ft
but it is also 11×12 + 8 = 140 in.
21 ft = 21×12 = 252 in.
14 ft = 14×12 = 168 in.
all we need to do now is simply divide for example the actual length (21 ft = 252 in) by the 140 in to see how many units of 1 in we need to see in the scale drawing.
252 / 140 = 18/10 = 9/5 = 1 4/5 = 1.8 in in the scale drawing.
so, the first answer option (1.8 in × 1.2 in) is the correct one.