Asmall rural town has experienced a population decrease at a rate of 25 people every 5 years since 1970. if the population of the town in 1970 was 250, which of the following equations represents the town’s population as a function of time? (assume 1970 is represented by x = 0, 1971 is represented by x = 1, and so on).

a. y = –5x + 250
b. y = –25x + 250
c. –5x + y = 250
d. –x – 25y = 250