I found out a bit of trivia - my former HIgh School tennis coach , Mark Davis , came up with the name for the ride I rode some with Carrolton Cycling Club - I love those guys ... Bob , Brenda , Kerry - you guys rock ! Scott and I rode most of the ride together - 85 miles or so ... Ryan hung with us for 25 miles then * poof * he was gone ! I really planned on going slow ... lol The group of Ryans friends did the first 25 miles in under an hour - I decided to dial it back but at 70 miles I still had an avg .

Generate a question about the above context.
What may be the reason for their friend disappearing ?
Select from: A. They rode ahead of them .. B. They had to use the restroom .. C. They are so fast , they could n't be seen .. D. None of the above choices ..