On the grid shown, Jane starts at dot A. She tosses a fair coin to determine which way to move. If she tosses a head, she moves up one dot. If she tosses a tail she moves right one dot. After four tosses of the coin, Jane will be at one of the dots P, Q, R, S, or T. What is the probability that Jane will be at dot R?
Answer Choices
A. \frac{1}{2}
B. \frac{3}{8}
C. \frac{9}{16}
D. \frac{7}{16}
E. \frac{5}{16}