Finding F's complement of a number

Question

Given answer: C. Please tell me how to approach this problem. 

Answer 1

its base 15 means . the system will have 15 number - 0 to E. And 15 is represented as F . so it is asking the radix complement of the number, now the radix complement can be written as  dimnishd radix complement + 1.

so dimnished radix  biggest number of n digit - number.

here biggest digit is e . so

eeee- 3a2e = b4c0

radix will be b4c0 + 1 = B4C1