The angles of elevation of the top of a tower from two points at distances p and q from the base and on the same straight line are 27° and 63° respectively. What is the height of the tower?

• A. pq
• B. \(\sqrt {pq} \)
• C. \(\frac{{pq}}{2}\)
• D. \(\frac{{\sqrt {pq} }}{2}\)