Select the most appropriate option that can substitute the highlighted segment in the given sentence.
Don’t disturb the boy, he prepares for his examination.

Correct option is B

The correct answer is (b) is preparing.
• The given sentence is in the present tense, and it describes an ongoing action (preparing for an examination).
• The correct form to use for an ongoing action in the present tense is the present continuous tense, which is formed using "is/are/am" + the present participle (-ing form) of the verb.
• In this case, "is preparing" is the correct substitution for the highlighted segment.