SAT Question de799680: Ratios Rates Proportional Relationships And Units answer and explanation with Desmos solution

Choice C is correct. It's given that $1$ centimeter = $10$ millimeters . It follows that a velocity of $76$ centimeters per second is equivalent to $\left(\frac{76\text{centimeters}}{1\text{second}}\right)\left(\frac{10\text{millimeters}}{1\text{centimeter}}\right)$, which is equivalent to $\left(76\right)\left(10\right)$, or $760$, millimeters per second.