Scurvy is:
a) A disease caused by deficiency of vitamin C and characterized by spongy bleeding gums, bleeding under the skin, and weakness
b) Extreme dryness of the conjunctiva resulting from a disease localized in the eye or from systemic deficiency of vitamin A
c) A disease caused by deficiency of niacin in the diet and characterized by skin eruptions, digestive and nervous system disturbances, and eventual mental deterioration
d) All of the above
