Each of the following items consists of a sentence followed by four words or group of words. Select the antonym of the word (occurring in the sentence in capital letters) as per the context. It is $COMPULSORY$ that all members of the board be present at the meeting.

• Correct answer
  A

  optional
• B

  contrary
• C

  obligatory
• D

  conditional

Hence, the correct answer is option: 'A'.