find the first six terms of the sequence. a1 = -6, an = 4 • an-1 select one: a. 0, 4, -24, -20, -16, -12 b. -24, -96, -384, -1536, -6144, -24,576 c. -6, -24, -20, -16, -12, -8 d. -6, -24, -96, -384, -1536, -6144