Correct Answer:
Option C - There is an error in part (c); there will be used 'was' able to help me' in the place of 'were able to help me' because when 'or' or 'nor' Joins two parts of a subject, the verb that follows should agree with the closest part to it, or according to 2nd sub of the sentence
C. There is an error in part (c); there will be used 'was' able to help me' in the place of 'were able to help me' because when 'or' or 'nor' Joins two parts of a subject, the verb that follows should agree with the closest part to it, or according to 2nd sub of the sentence