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: A bag is filled with pennies and nickels in the ratio of 5 to 3. There are 30 nickles in the bag, how many coins are there in that bag?

 Option A: 70

 Option B: 65

 Option C: 75

 Option D: 85

 Option E: 80
[A]: Option E


[Q]: Question: A reduction of 20% in the price of salt enables a lady to obtain 25 kgs more for Rs.100, find the original price per kg?

 Option A: 6

 Option B: 1

 Option C: 5

 Option D: 4

 Option E: 7
[A]: Option B


[Q]: Question: What is the product of all the prime factors of 15?

 Option A: 12

 Option B: 3

 Option C: 4

 Option D: 15

 Option E: 20
[A]:
Option D