Answer:
c .Perfect square trinomials
d.Difference of perfect squares
Explanation:
We have to find the special product formulas.
a.Perfect square monomials
It is of the form

It is not a special product formulas.
b.Difference of terms
It is of the form

It is not a special product formulas.
c.Perfect square trinomials
It is of the form

It is a special product formulas.
d.Difference of perfect squares
It is of the form


Therefore, it is a special product formulas.