Directions: The underlined part of the sentence below may have some errors. Five options are given below the sentence. Choose the option that improves the sentence. If the sentence has no error, choose option 5 as your answer.

I went to mohan's office who is my cousin brother and does the job in Delhi.

Here, 'the office of Mohan' rectifies the error of using 'Mohan's office'. Antecedent of a relative pronoun should be placed just before it. Here, 'Mohan', the antecedent of the relative pronoun 'who' is placed just before 'who'. Omision of 'brother' rectifies the error of using  it with 'cousin'. 'Cousin brother' is a slang use.