If (x - 2)(x - p) = x2 - ax + 6, then the value of (a - p) is?

Answer: Option C

$$\begin{array}{rl}& \left(x-2\right)\left(x-p\right)=x^2-ax+6\\ & x^2-\left(2+p\right)x+2p=x^2-ax+6\\ & \text{Comparision the cofficients}\\ & 2+p=a\\ & 2p=6\\ & \iff p=3\\ & 2+3=a\\ & \iff a=5\\ & \text{Then , }\\ & p=3,a=5\\ & a-p=5-3\\ & \iff a-p=2\end{array}$$