SAT Question 0a99e5bb: Probability And Conditional Probability answer and explanation with Desmos solution

Choice B is correct. If a number from the data set is selected at random, the probability of selecting a negative number is the count of negative numbers in the data set divided by the total count of numbers in the data set. It's given that a data set of three numbers is shown. It follows that the total count of numbers in the data set is $3$. In the data set shown, $-13$ is the only negative number. It follows that the count of negative numbers in the data set is $1$. Therefore, if a number from the data set is selected at random, the probability of selecting a negative number is $\frac{1}{3}$.