Final Answer:
The line segment longer than AB is D. TU.
Step-by-step explanation:
To determine the longer line segment, we compare the lengths of each segment to AB. In this case, TU is longer than AB. The notation indicates that T is one endpoint of the segment, and U is the other. When comparing line segments, the one with a greater distance between its endpoints is considered longer. Therefore, the correct answer is D. TU.
This question is assessing understanding of basic geometry and the concept of comparing line segment lengths. It assumes knowledge of the order of letters in the alphabet to correctly interpret the given segments.
Option D is the answer.