A) -2
Explanation on pictures
For step 3 where it says Simplify the only thing it has is -2
First you want to convert the cups of flour so that they have common denominators:
2 2/3 = 2 16/24
3/8 = 9/24
The subtract! 2 16/24 - 9/24 = 2 7/24 cups
.00000000058 because the exponent is negative the decimal goes backwards 10 times