When are ARFF firefighters available for emergencies? when the airport is open for business

thirty minutes before and after the first and last flights

twenty-four hours a day, three hundred sixty-five days a year

from sunrise to sunset, three hundred sixty-five days a year

the answer would be voluntary exchange -

"the act of buyers and sellers freely and willingly engaging in market transactions. moreover, transactions are made in such a way that both the buyer and the seller are better off after the exchange than before it occurred."

hope this : )

-shy