Answer:
Step-by-step explanation:
Hello, please consider the following.
A. (x minus y)(y minus x)

This is not a difference of squares.
B. (6 minus y)(6 minus y)

This is not a difference of squares.
C. (3 + x z)(negative 3 + x z)
This is a difference of squares.

D. (y squared minus x y)(y squared + x y)
This is a difference of squares.

E. (64 y squared + x squared)(negative x squared + 64 y squared)
This is a difference of squares.

Hope this helps.
Do not hesitate if you need further explanation.
Thank you