Answer:
General
Step-by-step explanation:
Hi, I noticed your question has yet to be answered, so I'll help you out and explain why this would be general usage.
Because it is an oral report, the answer would not be informal. So we have to focus on the remaining two and look at all the avenues in each.
Formal writing does not allow contractions, opts for complex terms and is often seen in masterful/scholarly writing. Because the audience is a church's youth group, more than likely formal usage is not the case. If it were an adult audience, perhaps this would be the right choice.
Therefore, general writing is not informal per say, but it does allow some contractions, explores modern/more simple of terms and is found in more comfortable environments, as opposed to formal.
Once again, because the audience is young, it would be very confusing if the person presenting the report were to use complex terms. They would have to word it in a way where the children could understand; hence, why I say general is correct.
Hope this helps.