A frog hops along the number line according to the following rules:
- It starts at 0.
- If it is at 0, it moves to 1 with probability \dfrac{1}{2} and disappears with probability \dfrac{1}{2}.
- For n=1,2,3, if it is at n, it moves to n+1 with probability \dfrac{1}{4}, to n-1 with probability \dfrac{1}{4}, and disappears with probability \dfrac{1}{2}.
What is the probability that the frog reaches 4?
Answer Choices:
A. \dfrac{1}{101}
B. \dfrac{1}{100}
C. \dfrac{1}{99}
D. \dfrac{1}{98}
E. \dfrac{1}{97}