Last Sunday, in a sermon, the pastor shared a moment of the East Side Bible fellowship on Friday where the question of "What is the purpose for Jesus to come" asked by the teacher. It was emphasized to a point that only that verse's answer is correct (...I have come to do your will, O God) and that all other answers seemed to be less accurate if not wrong. And it is apparent that the pastor concurred.
I think that since the study of that day is on Hebrews 10:7, it doesn't mean that one should take the verse out of its context. Therefore, it is not right to disqualify an answer if it doesn't pertain to the verse in question unless it is only within that passage that the question refers to. So answers that are also found especially elsewhere in the Bible should be treated as it should: I am Come...to fulfil the law (Matthew 5:17), ...to Preach (Mark 1:38), ...to call sinners to repentance (Luke 5:32), ...to send a sword (Matthew 10:34-35)...etc. [Jamieson, Fausset and Brown Commentary of Heb 10:7]
I do fully agree the former answer is a very good one, John 6:38-39, however, I will not disregard the other answers as if they were of lesser value. Because by saying that the answer can only be the will of God, it is a disdain to some's intellect, as if accusing them contradicting the will of God with the other answers.
Thus, with the motive inspected, I would say that the question itself is immature. For if I wanted people to see importance of following the Will of God, I would not ask someone: Why do you eat your food? and expect to tell them they are wrong if they do not answer and only answer "Because it's the Will of God". Though it is important to teach the Will of God, this kind of pedagogy is downright deceptive and narcissistic.