BPP Revison Kit question.

I need help with one of the questions from the BPP revision kit.

Which of the following statements about external auditors is not correct? (Question 11.9)
A. External Auditors are appointed by shareholders of the company
B. The primary responsibilities of external Auditors is to investigate Financial irregularities and report them to shareholders
C. External auditors may rely on the work of internal Auditors if they first assess its worth
D. External Auditors are concerned with the financial records and the statements of the organization

Could someone explain which one is the correct answer and why?
Thanks