Consider the following combinational function block involving four Boolean variables $x$, $y$, $a$, $b$ where $x$, $a$, $b$ are inputs and $y$ is the output.f (x, y, a, b) { if (x is 1) y = a; else y = b; }Which one of the following digital logic blocks is the most suitable for implementing this function?

The given function assigns:

• $y = a$ when $x = 1$

• $y = b$ when $x = 0$

This behavior matches a 2-to-1 Multiplexor (MUX), where $x$ serves as the select input, $a$ and $b$ are the data inputs, and $y$ is the output ($y = x \cdot a + \overline{x} \cdot b$).

• Full adder performs addition of three binary inputs.

• Priority encoder outputs the binary representation of the highest-priority active input line.

• Flip-flop is a sequential storage element, whereas this function is purely combinational.

Therefore, C is the correct option.