If $2$ cups make $1$ pint, and you have $3$ cups, should the number of pints be bigger or smaller than $3$? Does that suggest multiplying or dividing by $2$?

Think of the conversion as a fraction: $\dfrac{1\text{ pint}}{2\text{ cups}}$. Multiply $3$ cups by this fraction so that the cup units cancel.

In Desmos, type 3/2 or 3*(1/2) to represent dividing 3 cups by 2 cups per pint.

Look at the numerical output Desmos gives for this expression; that value is the number of pints of milk needed. Match that value to the closest answer choice.

The problem tells you that $2$ cups $=$ $1$ pint. This means every pint contains $2$ cups of milk.

We want to know how many pints are in $3$ cups. Since there are $2$ cups in each pint, we divide the total cups by $2$:

The cup units cancel, leaving the number of pints.

Now calculate:

So $3$ cups of milk is $1.5$ pints. The correct answer choice is $1.5$.