Answer:
B. thermal stress
Step-by-step explanation:
Rocks are weakening due to alternate expansion and contraction of the rocks. Rocks are expanded when it undergoes the high temperature, then it becomes expanded due to distance between the particles which are distant to each other. If winter season comes, rocks undergoes the low temperature then it becomes contracted due to distance between the particles are close to each other. Exfoliation is the one type of mechanical weathering and Halocasty is the one of the physical weathering process.