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.
--------
Question: Question: Find the average of all prime numbers between 4 and 15.

 Option A: 30

 Option B: 4

 Option C: 9

 Option D: 8

 Option E: None

Answer: Option C


Question: Question: A train running at the speed of 60 km/hr crosses a pole in 21 seconds. What is the length of the train?

 Option A: 350 m

 Option B: 278 m

 Option C: 876 m

 Option D: 150 m

 Option E: 267 m

Answer: Option A


Question: Question: What is the sum of the prime factors of 121 and the prime factors of 7434

 Option A: 27

 Option B: 67

 Option C: 57

 Option D: 37

 Option E: 47

Answer:
Option D