Who should I do my child report on?

Ok so I have to do this report on a little child on the ages of 0-8 and we have to study them to see how they are. I cant decide if I want to do it on my little cousins Brian, Nathan, or Coleman. Brian is really really really bad, he is 4 years old and he has already been suspended from preschool for hurting another kid. He throws temper tantrums, hits, and uses foul language. He likes things his way. Like I said he is very very bad and hes only 4. Nathan is almost the complete opposite. He is a very sweet baby, he is 2 years old. He had a cleft pallate when he was born and he will have to be going through surgery until he is 7 Years old to have it completely fixed. He loves to give hugs, he is always smiling and he is very polite.He Always likes to see others happy and almost never complains. Coleman is like right in the middle of them hes sort of bad, sort of good. He likes to play games he can sometimes trow temper tantrums but generally he is a good kid. He is 3 years old. I am really having a hard time choosing which of my cousins to do the project on, please give me your opinions on who you think I should do, it would really help me out! Serious answers though please.