A function is defined by mapping f : A -> B such that A contains m elements and B contains n elements and m>n then number of one one functions are ________
(a) ^nCm x m!
(b) ^nCm x n!
(c) 0
(d) none of the mentioned
I had been asked this question during an internship interview.
My query is from Number of Functions topic in portion Basic Structures: Sets, Functions, Sequences, Sums and Matrices of Discrete Mathematics