SAT Question 842cec4d: Linear Inequalities answer and explanation with Desmos solution

Choice D is correct. It's given that during a portion of a flight, a small airplane's cruising speed varied between $150$ miles per hour and $170$ miles per hour. It's also given that $s$ represents the cruising speed, in miles per hour, during this portion of the flight. It follows that the airplane's cruising speed, in miles per hour, was at least $150$, which means $s\ge 150$, and was at most $170$, which means $s\le 170$. Therefore, the inequality that best represents this situation is $150\le s\le 170$.