Answer:
Option A is correct
Difference of squares identity should be used to prove 49-4 =45
Explanation:
Prove that : 49 - 4 = 45
Polynomial identities are just equations that are true, but identities are particularly useful for showing the relationship between two apparently unrelated expressions.
Difference of the squares identity:

Take LHS
49 - 4
We can write 49 as
and 4 as
.
then;

Now, use the difference of square identity;
here a =7 and b = 2

or
= RHS proved!
therefore, the difference of square polynomial identity should be used to prove that 49-4 =45