The following sentence has been divided into parts. One of them may contain an error. Select the part that contains the error from the given options. If you don’t find any error, mark ‘No error’ as your answer.

He knows that / he has no other option / but to work hard. 

The erroneous part is: but to work hard.

Key Points

• 'no other' and 'than' are correlative conjunctions.
• Correlative conjunctions are pairs of words that work together to join two elements of equal importance within a sentence.
• In this case, "no other" and "than" are used as a correlative conjunction to express a comparison or contrast between two options.
• In the sentence, "no other" is used to emphasize that there are no alternative options available. It suggests that the person referred to in the sentence has exhausted all possibilities and has only one option left.
• "Than" is used to introduce the only remaining option, which is to work hard.
• The combination of "no other" and "than" acts as a correlative conjunction because they work together to join the elements of the sentence, indicating the limited choices and emphasizing the necessity to work hard.
• Hence, 'than' must replace 'but' to make the sentence grammatically correct.

Therefore, the correct answer is: He knows that he has no other option than to work hard.