Aquadrilateral is a trapezoid. (always, sometimes, never)

Hello!

I believe that your answer is B.

"A quadrilateral is sometimes a trapezoid"

A quadrilateral is a figure w/ four sides as well as a trapezoid. However, not all figures w/ four sides are trapezoids. Some examples are a square and a rhombus. Both figures are four-sided but none of them are trapezoids. So a quadrilateral is sometimes a trapezoid

I hope this helps!