The answer is C.
First, you need to identify what items happen before 2/3 of an hour by seeing which decimals are equal to 2/3.
We know she will stretch her legs, because 1/3 times two is 2/3, it lines up just right. We also know she will stretch her arms, because 1/6 times four is 4/6, which can be reduced to 2/3.
She cannot stretch her neck, because 1/2 will not come out to 2/3 no matter how you multiply it.
Good luck!