Consider 4-variable functions $f1, f2, f3, f4$ expressed in sum-of-minterms form as given below.

$f1 = \sum(0,2,3,5,7,8,11,13)$

$f2 = \sum(1,3,5,7,11,13,15)$

$f3 = \sum(0,1,4,11)$

$f4 = \sum(0,2,6,13)$

With respect to the circuit given above, which of the following options is/are CORRECT?

Consider a digital logic circuit consisting of three 2-to-1 multiplexers M1, M2, and M3 as shown below. X1 and X2 are inputs of M1. X3 and X4 are inputs of M2. A, B, and C are select lines of M1, M2, and M3, respectively.

For an instance of inputs **X1=1**, **X2=1**, **X3=0**, and **X4=0**, the number of combinations of A, B, C that give the output **Y=1** is ______________

The minimal sum of products form of the output $$X$$ is

The minimal sum-of-products form of the Boolean expression for the output $$F$$ of the multiplexer is