You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.

Q: Question: The average age of 15 students of a class is 15 years. Out of these, the average age of 4 students is 14 years and that of the other 10 students is 16 years, The age of the 15th student is

 Option A: 11

 Option B: 12

 Option C: 9

 Option D: 14

 Option E: 15

A: Option C
****
Q: Question: A and B rent a pasture for 10 months. A put in 80 cows for 7 months. How many can B put in for the remaining 3 months, if he pays half as much again as A?

 Option A: 388

 Option B: 277

 Option C: 266

 Option D: 280

 Option E: 191

A: Option D
****
Q: Question: 16, 23, 19, 19, 22, 15, 25, ?
What number should replace the question mark?

 Option A: 13

 Option B: 11

 Option C: 16

 Option D: 18

 Option E: 19

A:
Option B
****