Using the graph below, what are the common ratio and the general term equation, an, of the geometric sequence? hint: an = a1(r)n − 1, where a1 is the first term and r is the common ratio. options: r = 1/2, a sub n = -16 (1/2) to the power of n-1 r = −2, an = −16(−2)n − 1 r = 2, an = −16(2)n − 1 r = -1/2, a sub n = -16 (-1/2) to the power of n-1