When Jonathon Gerinum, CPA Tried to Collect Last Year's Audit

When Jonathon Gerinum, CPA tried to collect last year's audit fees, he was told that he would receive the fees for the previous year and the current year upon finishing this year's work
And issuing a "clean" audit opinion. This was non-negotiable and he was told that if he did not
Want to go along with it, the client would get another auditor. When he decided to leave his
Client, what threat to his independence did he mitigate?

A) self-interest threat
B) self-review threat
C) advocacy threat
D) none of the above