Positive real numbers x \neq 1 and y \neq 1 satisfy \log _{2} x=\log _{y} 16 and x y=64. What is \left(\log _{2} \dfrac{x}{y}\right)^{2} ?
Answer Choices
A. \dfrac{25}{2}
B. 20
C. \dfrac{45}{2}
D. 25
E. 32
Positive real numbers x \neq 1 and y \neq 1 satisfy \log _{2} x=\log _{y} 16 and x y=64. What is \left(\log _{2} \dfrac{x}{y}\right)^{2} ?
Answer Choices
A. \dfrac{25}{2}
B. 20
C. \dfrac{45}{2}
D. 25
E. 32