Question

Which of the following is an example of a close-ended question? Why do you enjoy fishing as a hobby? When is your birthday? What did you think of the test yesterday? Why do you like to exercise by jogging?

Answer 1

A close-ended question is one that can have only one answer - it is usually a yes/no question, but there are other types. These questions do not require a person to give lengthy answers, but rather a straight-to-the-point short answer.
Having this in mind, I'd say that the correct answer is When is your birthday? because there is only one answer here.