SAT Question 8bf3f67a: Ratios Rates Proportional Relationships And Units answer and explanation with Desmos solution

Choice A is correct. It's given that a special camera is used for underwater ocean research, and this camera is at a depth of $39$ fathoms. It's also given that $1$ fathom is equal to $6$ feet. Thus, $39$ fathoms is equivalent to $\left(39\text{fathoms}\right)\left(\frac{6\text{feet}}{1\text{fathom}}\right)$, or $234$ feet. Therefore, the camera's depth, in feet, is $234$.