Answer: "Did you put the key in your pocket?" is D. a closed question.
Explanation: "Did you put the key in your pocket?" is a closed question because it can be answered just by saying "yes" or "no". It does not encourage the person that has to give an answer to add further information since a single word/phrase is enough. In that way, this question could never be considered an open-ended question since open-ended questions encourage a full and meaningful answer.
