Question: Why is it that anti-virus scanners would not have found an exploitation of Heartbleed?
A: It's a vacuous question: Heartbleed only reads outside a buffer, so there is no possible exploit 
B: Anti-virus scanners tend to look for viruses and other malicious
C: Heartbleed attacks the anti-virus scanner itself
D: Anti-virus scanners tend to look for viruses and other malicious code, but Heartbleed exploits steal secrets without injecting any code 
Please eliminate two incorrect options first, then think it step by step and choose the most proper one option.