Final answer:
Unlocking of the subtalar joint during supination would most likely assist the foot with adapting to walking on a rocky surface.
Step-by-step explanation:
The correct answer would be C. Unlocking of the subtalar joint during supination. Supination is the movement of the foot that involves the foot turning inward, allowing the bottom of the foot to face towards the midline of the body. Unlocking of the subtalar joint during supination helps the foot adapt to walking on a rocky surface by allowing the foot to better absorb shock and maintain stability.