a local government is planning to build new roads that will divide a forest into several fragments the roads can follow several different designs each of which design will minimize the edge effect on the organisms living in the forest ?
This is a question about Ap environmental science but it is math related so
I see that the appropriate choice is "four rectangle fragment which is 5 miles wide and 6 miles long "
because that will minimize the edge effect
anybody here have a different opinion ?

As long as we are asking about opinions, note that the edge effects are more severe with smaller territories. So it is not only perimeter that is important, as deep woods animals need deeper woods, so you should never say "4 fragments" because that is more fragmented. I took APES and got a 5.
Mathematically, calculate the perimeter by adding the two given lengths and multiplying by the number of fragments