Answer:
Option (a) is correct.
The factored form of given expression
is 
Step-by-step explanation:
Given expression 
We have to factorize the given expression completely.
Consider the given expression 
We will solve the given expression by grouping terms and taking common factor common.

Taking
common from first two terms and -4 common from last two terms, we have,

Taking (x+6) common , we have,

Also , using algebraic identity 
We have a = x , b = 2
We have,


Thus, the factored form of given expression
is 