Debra flips a fair coin repeatedly, keeping track of how many heads and how many tails she has seen in total, until she gets either two heads in a row or two tails in a row, at which point she stops flipping. What is the probability that she gets two heads in a row but she sees a second tail before she sees a second head?
Answer Choices
A. \dfrac{1}{36}
B. \dfrac{1}{24}
C. \dfrac{1}{18}
D. \dfrac{1}{12}
E. \dfrac{1}{6}