SAT Question 2493c767: Linear Functions answer and explanation with Desmos solution

Choice C is correct. It's given that $s\left(x\right)$ is the number of spoons remaining in a dispenser $x$ minutes after the dispenser had been loaded with spoons. The expression $s\left(3\right)$ represents the value of $s\left(x\right)$ when $x=3$. It follows that $s\left(3\right)$ represents the number of spoons remaining in the dispenser $3$ minutes after it had been loaded with spoons. Therefore, the best interpretation of the equation $s\left(3\right)=121$ is that there were $121$ spoons remaining in the dispenser $3$ minutes after it had been loaded with spoons.