Choice C is the correct answer. The initial value is the coefficient $a$.

1. Identify: In $y = ab^x$, $a$ is the starting amount.
2. Locate: $a = 50$.
3. Verify: At $w=0$, $S(0) = 50(1.1)^0 = 50(1) = 50$.

💡 Strategic Tip: Always plug in $t=0$ or $w=0$ to find the initial value.

Choice B is incorrect because 1.1 is the growth factor. Choice D is incorrect because 55 is the number after 1 week.