The following formulas give the populations (in 100's) of four different cities where $t$ is in years. For each equation, decide whether the relationship is exponential, linear, or neither:

(a) $P_A = 1450(0.975)^t$   is Choose Exponential Linear Neither

(b) $P_B = 85(1.025)^t$   is Choose Exponential Linear Neither

(c) $P_C = 1200 + 0.79 t$   is Choose Exponential Linear Neither

(d) $P_D = 29(2.2)^t$   is Choose Exponential Linear Neither