I still don't agree with you. I asked:

"which of the following wildcard characters"

To me that implies that [] is a wildcard set of characters. I think asked

"can match a single character"

Meaning, can I use one or more of the wildcards to match a single character.

Most people understood. Perhaps we're all wrong, but I fail to see how the question isn't clear unless you are trying to read the letters without realizing the spirit.