Choice A is the correct answer. Solve for $t$ when $h(t) = 300$.

1. Equation: $300 = 400e^{-0.001t}$.
2. Divide: $0.75 = e^{-0.001t}$.
3. Natural log: $\ln(0.75) = -0.001t$.
4. Solve: $t = \frac{\ln(0.75)}{-0.001} = \frac{-0.288}{-0.001} \approx 288$ days.

💡 Strategic Tip:$\ln(0.75) = \ln(\frac{3}{4}) \approx -0.288$.

Choice B is incorrect because this is too long. Choice C is incorrect because this is too short. Choice D is incorrect because this is way too long.