C. Every year the number of subscribers is estimated to increase by 8% over the
number of subscribers the year before.
Step-by-step explanation:
Using the formula :
S = 20,000 (1 + 0.08)^y to estimate ;
S = number of subscribers ; y = years
The expression : (1 + 0.08)^y
0.08 = 0.08 * 100% = 8%
(1 + 0.08)^y represents a continous growth or increase in the number of subcsribers by 8% over the number of subscribers the preceeding year