Answer:
D
Step-by-step explanation:
The rules we need to simplify this are:
[tex]a^x*a^y=a^{x+y}[/tex]
and
[tex](a^x)^y=a^{xy}[/tex]
Now, let's simplify the problem:
[tex](y^{-7}*y^{-3})^{-1}\\(y^{-10})^{-1}\\y^{10}[/tex]
Answer choice D is y^10, so that's correct.