Read the following context and choose the best option to answer the question.
Context: Plus , I got to hear the worst riddle I ' ve ever heard from a bum . " What 's the best nation there is ? " " Uh , Kenya ? " " No , a donation . "
Question: What may be the reason for a bum giving them a riddle ?
Options: 
A. None of the above choices .
B. To let them through .
C. To test their knowledge .
D. To earn money from them .


D