Emily collects and trades rocks. She starts with 8x^2 rocks, for some number x, and then buys 7x^2. She then trades away x^2, then gives away 9x, and finally sells another 5 rocks. Write an expression for the number of rocks Emily now has in standard form. A. −9x + 8x^2 + 7x^4 − 5 − x^5
B. 8x^2 − 5 + 7x^4 − 9x − x^5
C. −x^5 + 7x^4 + 8x^2 − 9x − 5
D. −5 − 9x + 8x^2 + 7x^4 − x^5