SAT Question a5b069b4: Distributions, Center & Spread answer and explanation with Desmos solution

Choice B is correct. If a data set contains an even number of data values, when the data values are listed in ascending or descending order, the median is between the two middle values. The given data set contains $8$ values. When listed in ascending order, the data set is $4$, $4$, $4$, $5$, $5$, $6$, $10$, $18$ and the two middle values are $5$ and $5$. Since the two middle values are the same, the median must be $5$.