SAT Question c81499e1: Ratios Rates Proportional Relationships And Units answer and explanation with Desmos solution

It’s given that the giant armadillo has a mass of $39$ kilograms. Since $1$ kilogram is equal to $1,000$ grams, $39$ kilograms is equal to $39\text{kilograms}\left(\frac{1,000\text{grams}}{1\text{kilogram}}\right)$, or $39,000$ grams. Therefore, the giant armadillo’s mass, in grams, is $39,000$.