My take is C.
The author says that
"same clues are used by both
" which means the clues are definitely provided
hence it IMHO it is C.
- not mentioned in the argument
B. may or may not be true. User is given chance to solve mystery, user need not solve it.
D - Cannot be infered. It's only the actions of the dumb guy that divert. Nothing is said about the brilliant guy.
E - Arg doesn't mention that the dumb guy "uncovers" the misleading clues. We only know that he interprets them incorrectly.
"To dream anything that you want to dream, that is the beauty of the human mind. To do anything that you want to do, that is the strength of the human will. To trust yourself, to test your limits, that is the courage to succeed."
- Bernard Edmonds