Q: You are presented with the quiz "What causes skin to become red and painful to the touch?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "ultraviolet light causes sunburn" and "sunburns cause the skin to become red and painful to the touch". So, what's the best answer to the question?

i. skin lotion. ii. chemical messengers. iii. lightening creams. iv. chemical reaction. v. ultraviolet light. vi. lightening skin. vii. sensory neurons. viii. deoxyribonucleic acid.
A:
v.