Choice C is the correct answer. The coefficient $a$ is the y-intercept.

1. Identify: $a = 5000$.
2. Interpret: This is the value when $x=0$, which is the y-intercept (initial value).

💡 Strategic Tip: Initial value = Starting amount = Y-intercept.

Choice A is incorrect because the rate is 0.03. Choice B is incorrect because the factor is 1.03.