Choice B is the correct answer. Identify components in $y=ab^x$.

1. Identify a: The coefficient is 80, so the initial value is 80.
2. Identify b: The base is 0.75.
3. Classify: Since $0 < 0.75 < 1$, it represents decay.

💡 Strategic Tip: A decimal base like 0.75 means you are keeping 75% of the value, so it's shrinking.

Choice A is incorrect because 0.75 implies decay, not growth. Choice C is incorrect because it swaps $a$ and $b$. Choice D is incorrect because 0.25 is the decay rate (25%), not the factor.