So, you have i to the 37th. I’m guessing you’ve learned that i to the 4th is one. If you haven’t, it is. Taking that into account, if you divide 37 by 4, you get 9 and 1/4. so, you have 9 i^4’s and one i^1. That is the same as i^1 because 1 times anything is itself. i^1 is just i, so i is the best answer. Hope that helped!