When an Airline Overbooks and Passengers Must Be Bumped, Which

When an airline overbooks and passengers must be bumped, which of the following is the correct order for determining which passengers are bumped?

A) Volunteers, followed by the last to arrive at the gate
B) The airline's priority rules, followed by the last to arrive at the gate
C) Volunteers, followed by the airline's priority rules
D) The last to arrive at the gate followed by volunteers