Let A B C D be a rhombus with A C=16 and B D=30. Let N be a point on \overline{A B}, and let P and Q be the feet of the perpendiculars from N to \overline{A C} and \overline{B D}, respectively. Which of the following is closest to the minimum possible value of P Q ?
Answer Choices
A. 6.5
B. 6.75
C. 7
D. 7.25
E. 7.5