Answer:
B. Its threads run parallel instead of at right angles to each other.
Denim's durability can be attributed to the way it is woven. The threads in denim fabric run parallel to each other, which gives it strength and resistance to wear and tear. This weaving technique, known as twill weave, contributes to the fabric's robustness and longevity. The other options mentioned (A, C, and D) are not accurate explanations for why denim is durable.