Identify the sequence as arithmetic (linear) or geomteric (exponential) and write a recursive expression to represent the sequence. 100, 85, 70, 55, 40, ... a arithmetic tn =tn-1 + 15 b geometric tn = tn-1 - 15 c arithmetic tn = tn-1 - 15 d geometric tn = tn-1 + 15