Choice A is the correct answer. This real-world problem requires setting up and solving an inequality.

1. Set up: Total score is $42 + s$, need "at least 85" means $42 + s \geq 85$
2. Solve: Subtract 42: $s \geq 85 - 42$
3. Calculate: $s \geq 43$

?�� Strategic Tip: "At least" translates to $\geq$ (greater than or equal to), indicating a minimum threshold.

Choice B is incorrect because$\leq 43$ would represent a maximum score, not a minimum. Choice C is incorrect because it adds 42 and 85 instead of subtracting, misunderstanding the operation needed. Choice D is incorrect because while this setup is partially correct in form, it uses $\leq$ instead of $\geq$, contradicting "at least".