A study was done to investigate the population of a certain species of animal over time. The correlating linear model is shown below, where x represents the number of years after 1955, and y represents the number of that certain species. Interpret the y-intercept.

y = 5,000 + 500x

A. There were 1,000 of that species in 1955.
B. There were 10,000 of that species in 1955.
C. There were 500 of that species in 1955.
D. There were 5,000 of that species in 1955.