The answer would be C because you are adding them together to get the perimeter. So you add 1x^2+3x^2 which gives you 4x^2. I got the 1 because there is always an invisible 1 in front of a single variable. Then you add 3x+-2x which then if you do skip, change, change it turns into 3x-2x which leaves you with 1x or x. Finally you add 6+-5 and again you do skip, change, change so you then have 6-5 which gives you 1. Now put it all together 4x^2+x+1. So that leaves you with C as your answer.