Answer:
line segment BE
Explanation:
Parallel lines are lines that never cross. In this case, the two parallel lines are AC and DF. A line segment is part of a line that has a point at either end. The only segment which crosses lines AC and DF is segment BE.
Also, if you look at the answer choices, the first two indicate a line ↔ above the letters, which represents a line that doesn't end, while the other two choices just have a line to indicate a segment.