Choice A is the correct answer. Interpret slope.

1. Slope: $2.5$. This means for every $1 increase in x, y increases by $2.5.
2. Increase: If x increases by 100, y increases by $2.5 \times 100 = 250$.

💡 Strategic Tip: Change in y = Slope $\times$ Change in x.

Choice B is incorrect because it's the change in x. Choice C is incorrect because it's the slope. Choice D is incorrect because it adds the base.