Need help understanding this problem..

If a population is changed by either immigration or emigration, a model for the population is dy/dt= Ky + f(t) where y is the population at time t and f(t) is some function of t that describes the net effect of the emigration/immigration. Assume that k = 0.02 and y(0) = 10,000. Solve this differential equation for y, given that

	y = 1100t + 55,000 + 65,000e-0.02t
	y = 1100t - 55,000 + 65,000e-0.02t
	y = -1100t - 55,000 + 65,000e0.02t
	y = -1100t - 55,000 + 65,000e-0.02t