1)You, he and I (A)/are (B)/ in the wrong. (C)/ No error (D).
Error in part A
Use ‘I, you and me’ instead of ‘you, he and I’.
2)Those two (A)/ teams always (B)/help one another (C)/No error (D).
Error in part C
Use ‘each other’ instead of ‘one another’.
3)One (A)/ should love (B)/ his country (C)/ No error (D).
Error in part C
Use ‘one’s’ instead of ‘his’.
4)I introduced (A)/to the president as (B)/the manager of the company (C)/No error (D).
Error in part A
Use reflexive Pronoun 'himself' after 'introduced'.
5)This is (A)/the same dog (B)/which barked at him (C)/ No error (D).
Error in part C
Use ‘that’ instead of ‘which’.
6)This is (A)/ the best (B)/ thing which I can do (C)/ No error (D).
Error in part C
Use ‘that’ instead of ‘which’.
7)The price was (A)/ given to the girls (B)/ whom they said stood first (C)/ No error (D).
Error in part C
Use ‘who’ instead of ‘whom’.
8)I like (A)/ you more (B)/ than he (C)/ No error (D).
Error in part C
Use ‘him’ instead of ‘he’.
9)He (A)/ is better (B)/ than me (C)/ No error (D).
Error in part C
Use ‘I’ instead of ‘me’.