The correct answer is warm up and practice difficult names.
Explanation:
For this answer, let's discard options:
The first one suggests the speaker record other people's voice; even though it might be helpful to test the equipment, its help might be very limited for one's voice.
Letter C is also incorrect because the speaker wants to speak and not to listen to anything but his own voice.
Letter B is the correct answer because with the warm up the speaker can be ready for changing his voice when required, while practicing difficult names might improve pronunciation.
