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

y = 5,000 + 500x

AThere were 10,000 polar bears in 1955.
BThere were 1,000 polar bears in 1955.
CThere were 5,000 polar bears in 1955.
DThere were 500 polar bears in 1955.