Minimum number of 2 x 1 multiplexers required to realize the following function, $$f= \overline{A} \overline{B} C + \overline{A} \overline{B} \overline{C}$$.
Assume that inputs are available only in true form and Boolean a constant 1 and 0 are available.

A

1

B

2

C

3

D

7