Let A = [7, 5] and B = [6, 8]. Find the total number of relations from A into B.

Correct option is A

Given A = [7, 5] and B = [6, 8].
n(A) = n(B) = 2
The Cartesian product A×B consists of all possible ordered pairs (a,b) where a∈A and b∈B. Since A has 2 elements and B has 2 elements:
∣A×B∣=2×2=4
The number of subsets of a set with n elements is 2n.
Total number of relations=24=16