A company's monthly profit increases by $1,000 each month. In January, the profit of the company was $25,000. If x = 0 represents January, which of the following equations represents the profit as a function of time (in months)?
A. y = 25,000x + 1,000
B. y = 1,000x
C. y = 1,000x – 25,000
D. y = 1,000x + 25,000