When Does a Pocket Veto Occur

When does a pocket veto occur?

A) when the president does nothing upon receipt of a bill from Congress
B) when the president takes no action within 10 days of receiving the bill from Congress and Congress adjourns within those 10 days
C) when the president vetoes a bill from Congress during a lame-duck session and the Congress adjourns immediately thereafter
D) whenever the president vetoes a bill