Under the York-Antwerp Rules, what are the necessary elements for a sacrifice or expenditure to qualify as a general average act?

(1) The sacrifice or expenditure must be extraordinary. 

(2) The sacrifice or expenditure must be reasonable. (3) The act must be intentional or voluntary, and not inevitable. (4) There must be a peril. (5) The action taken must be for the common safety and not merely for the safety of part of the property involved.