Simplify the following expression

(5p^9 q^3) (2pq^7)
A. 10p^8 q^-4
B. 10p^10 q^10
C. 7p^10 q^10
D. 10p^9 q^21

To simplify the expression (5p^9 q^3)(2pq^7), we can simplify the numbers and multiply the variables together.

First, we simplify 5 * 2 = 10.

Next, we multiply the p's. We add the exponents: p^9 * p^1 = p^(9+1) = p^10.

Lastly, we multiply the q's. We add the exponents: q^3 * q^7 = q^(3+7) = q^10.

Therefore, the simplified expression is 10p^10q^10.

The answer is B. 10p^10q^10.