Subject: mathqa
Question: there are 4 people of different heights standing in order of increasing height . the difference is 2 inches between the first person and the second person , and also between the second person and the third person . the difference between the third person and the fourth person is 6 inches and the average height is 75 . how tall is the fourth person ?
Option: 
A: 73
B: 75
C: 81
D: 79
Answer: C