The worst question of the bunch is undoubtedly the tennis question. A very clever alien could answer the other six, but having never been exposed to the rules

The worst question of the bunch is undoubtedly the tennis question. A very clever alien could answer the other six, but having never been exposed to the rules of tennis would be hopeless against the Wimbledon question. (In fact my knowledge of tennis is poor enough that I don't understand why the question would be considered difficult for somebody who played tennis.)