Which research question would be most appropriate for a four- to five-page research paper?

what causes childhood obesity?
should the government impose restrictions on what kinds of foods can be served in school cafeterias?
how do french fries affect the brain?
as of last year, how many obese adults in the us were also once obese children?

the correct answer is "Should the government impose restrictions on what kinds of foods can be served in school cafeterias? "

Explanation: since it is a very debatable topic and the arguments can be long, the best answer is the mentioned above.

direct attacks on us ships

germany’s attempted alliance with mexico

a desire to preserve democracy in the world

i believe that the answer is c, but i'm not entirely sure.