On a test, Marcus is asked to simplify . Here is his work: = · =

Which statement best describes Marcus' answer?

1. He is incorrect because 16 times 8 is not 128.
2. He is incorrect because the 4 and the 8 should be switched around in his answer.
3. He is correct.
4. He is incorrect because he did not use the largest perfect square.

Hope you understand it before you answer I already know the answer but want to see how smart you guys really are :)