It was quite easy to tune out the patter around him, as Justin focused on the delicate task before him.
Based on the context of this sentence, what does patter mean?
A. A specialized language, especially the jargon of criminals (as thieves)
B. Empty, chattering talk
C. To run with quick, light-sounding steps
D. To say or speak in a rapid or mechanical manner
Which one is it? Please help