A User Installs an Expensive New Microphone on a Desktop

Multiple Choice

A user installs an expensive new microphone on a desktop. Now, every time the user boots the machine, the speakers give loud feedback. Which of the following caused this issue?

A) The CPU is running too hot.
B) The wrong audio card is installed.
C) The speaker is not compatible with the microphone.
D) The microphone is too close to the speaker.