In each of the following questions, one phrase has been given and it has been followed by four sentences. You have to find out in which of these sentences the phrase has been used properly according to its meaning and mark your answer from the options. Mark your answer 'all correct' if you find that phrase has been applied properly in all the sentences.

bang (one's) head against a brick wall

I. I feel like I've been banging my head against a brick wall trying to understand this math equation.

II. Some people are never going to agree with you on this, so it's no use banging your head against a brick wall trying to convince everyone.

III. If that team finishes second in the division, who will bang their head against a brick wall.

IV. Are you willing to stand against such a powerful company in the courts or bang your head against a brick wall.