Fist draw a table of the sequence with each number's corresponding n value.1 2 3 4 5 9 16 25 36 49Now draw a table for each option and see if it matches, it is important to remember to carry out the sum within the brackets first .A. n^2 when n= 1, n^2= 1^2 = 1 this is not 9 and therefore cant be AB. (3n)^2when n= 1 , (3n)^2= (3x1)^2 = 9when n= 2 , (3n)^2= (3x2)^2 = 36 which is not 16 and therefore cant be BC. (n+2)^2when n=1, (n+2)^2 = (1+2)^2 = 9when n=2, (n+2)^2 = (2+2)^2 = 16when n=3, (n+2)^2 = (3+2)^2 = 25when n=4, (n+2)^2 = (4+2)^2 = 36when n=5, (n+2)^2 = (5+2)^2 = 49. Therefore the answer must be C.