Please help i dont know if it is a or c

State one method by which you can recognize a perfect square trinomial.

Find the amplitude of a sinusoidal function that models this temperature variation

Use mathematical induction to prove the statement is true for all positive integers n, or show why it is false. 1^2 + 4^2 + 7^2 + + (3n - 2)^2 = [n(6n^2-3n-1)/2]