The population of a city grows at a rate of 2,000 people per year. If the population is initially 100,000 people, which of the following equations represents the population (P) in terms of the number of years (t)?
a. P = 2,000t + 100,000
b. P = 2,000t - 100,000
c. P = 100,000t + 2,000
d. P = 100,000t - 2,000