Which of the sentences below best expresses the essential information in the highlighted s

entence in the passage？ Incorrect choices change the meaning in important ways or leave out essential information.

A．Vitamin A deficiency results in night blindness, which is also known as nyctalopia in medical terms.

B．The earliest sign of vitamin A deficiency is night blindness.

C．Among many disorders caused by lack of vitamin A, night blindness is the most common.

D．Vitamin A deficiency may cause many different types of ailments especially involving the eyes, including nyctalopia.