The population, in millions, of a city t years after 1990 is given by p(t)=3.1+0.07t a. 3.1 million is the population of the city in 1991 and 3.17 million is the population in 1992. c. 3.1 million is the population of the city in 1990 and 0.07 million is the increase per year in the population. b. 3.1 million is the population of the city in 1990 and 0.07 million is the decrease per year in the population. d. 0.07 million is the population of the city in 1990 and 3.1 million is the increase per year in the population.