Task: Question Answering
Input (English): Question: The function f is defined for all positive integers n by the following rule: f(n) is the product of the distinct prime factors of n. If f(n) < 30 and n is not prime, what is the greatest possible value of f(n)?

 Option A: 28

 Option B: 26

 Option C: 20

 Option D: 18

 Option E: 15
Output (English): Option B