CAT 2017 [slot 2] Question with solution 31

Question 65:
If f(ab) = f(a)f(b) for all positive integers a and b, then the largest possible value of f(1) is

Answer: 1
Explanation:

f(1 × 1) = f(1)f(1)
=> f(1) = f(1)f(1)
=> f(1) = 0 or f(1) = 1
Hence maximum value of f(1) is 1