Answer:
Last choice.
Step-by-step explanation:
We can factor the expression by using the following formula.
[tex] {x}^{2} - {y}^{2} = (x + y)(x - y)[/tex]
From the expression,
[tex](3 {x}^{2} )^{2} - {(7xy)}^{2} [/tex]
[tex](3 {x}^{2} + 7xy )(3 {x}^{2} - 7xy)[/tex]
