Select the correct answer. What is the simplified form of pi sqrt (3)-8pi sqrt (3)? A. -7sqrt (3)pi B. -9sqrt (3)pi C. -7pi D. -9pi

To simplify the expression $\pi \sqrt {3}-8\pi \sqrt {3}$, we can combine the terms by factoring out the common factor of $\pi \sqrt {3}$:<br /><br />$\pi \sqrt {3}-8\pi \sqrt {3} = (\pi - 8\pi) \sqrt {3} = -7\pi \sqrt {3}$<br /><br />Therefore, the correct answer is A. $-7\sqrt {3}\pi $.