24 students were surveyed since that is the entire class.
Part B:
We don't know what the survey was about so we can't answer this part.
Part C:
Since we aren't given information on what was surveyed, we can just assume that it was different categories and they were asked to choose something they like or own. If each student chooses what they like or have and it varies, the responses are going to be different than the survey since the response is choosing something and surveying is just the 24 students in class.
