Theorem: A line parallel to one side of a triangle divides the other two proportionately

Answer:
The correct option is D
BF = 18
Explanation:
Given that the segment DE is parallel to segment BC, and segment EF is parallel to segment AB.
Because a line parallel to one side of a triangle divides the other two proportionately, BF can be determined by using the ratio:
BF/24 = 27/36
BF = 27/36 * 24
= 18