Write an explicit formula for the following sequence. Then generate the fi a = 512, r = 0.25 Choose the correct explicit formula for the sequence. -1 A. an = 0.25 (512)" n>1 OB. an =512 (0.25)" for n > 1 C. an=512 (0.25)"-1 for n1 OD. an=512-1(0.25) for n 1 Generate the first five terms. a = (Simplify your answer.)