Night blindness (Hemeralopia, Nyctalopia) is
a) Extreme dryness of the conjunctiva resulting from a disease localized in the eye or from systemic deficiency of vitamin A
b) A condition, usually in children with vitamin A deficiency, characterized by softening and subsequent ulceration and perforation of the cornea
c) A condition of the eyes in which vision is normal in daylight or other strong light but is abnormally weak or completely lost at night or in dim light and that results from vitamin A deficiency
d) All of the above