I believe the answer is A.
The other values have repeated X values.
The answer is 15.3 because if you subtract 6.7 from 22 you’ll get the answer 15.3
He made 3.75 gallons. There was 1/10 remaining, meaning each tenth was 6 cups. The entire thing is 10 tenths so you do 6(10) to get 60 cups. After converting to gallons by doing 60÷26, you get 3.75.
5' per side or whatever units it's measured in, because 4x5=20