Choice C is the correct answer. Let $c$ be the cost of a croissant and $m$ be the cost of a muffin.

Given: $c = 2$ and $2c + 3m = 11$

Step 1: Substitute $c = 2$: $2(2) + 3m = 11$$4 + 3m = 11$

Step 2: Solve for $m$: $3m = 7$$m = \frac{7}{3} \approx 2.33$

Solution: One muffin costs approximately $$2.33$.

Verification: $2(2) + 3(\frac{7}{3}) = 4 + 7 = 11$ ✓

💡 Strategic Tip: When one variable is given, substitute immediately to simplify.

Choice A is incorrect because$2(2) + 3(2) = 4 + 6 = 10 \ eq 11$.

Choice B is incorrect because$2(2) + 3(2.5) = 4 + 7.5 = 11.5 \ eq 11$.

Choice D is incorrect because$2(2) + 3(3) = 4 + 9 = 13 \ eq 11$.