Which of the following is an open question? "where are you from? " "when did you graduate from college? " "why did you leave your last job? " "do you have transportation to work? "

"Why did you leave your last job?" is the correct answer.

Explanation:

"Why did you leave your last job?" is an open question.

Open questions are those which need more reasoned that is more than simple word response.

An open question where we cannot answer with yes or no response.

An open question requires a complete answer, applying the subject's information.

Thus In open questions, the answer needs a proper explanation.(Why did you leave your last job?" is an example of an open question as we cannot answer this question in yes or no it needs proper explanation.