Depending on the airport and the regulations in place, any vehicle can cross the runway provided it is in radio communication with the tower and has had clearance to cross. The would also need to advise the tower when they had cleared or "vacated" the runway.
In an emergency, the main vehicles given permission to cross or even enter the runway would be the "crash" trucks and the ATC supervisor. They would still need permission to enter the runway.
None of the above
None
none of the above
none of the above
None of the above have permission to croos the runway without contacting the Control Tower for approval
Emergency vehicles must always assume that a runway is being used for air traffic, even after an emergency landing. They must wait until cleared by the tower before moving onto the runway and not assume they can go once the emergency craft has landed.
The question is incomplete. There are no options given (for "which of the following") to answer this question.
False
According to the FAA, a runway incursion is "Any occurrence at an aerodrome involving the incorrect presence of an aircraft, vehicle or person on the protected area of a surface designated for the landing and take off of aircraft." It's "significant" because people get killed that way. Runway incursion results in collosion of aircraft on the ground when they are fully loaded with fuel and people. Runway incursion is when something enters an active runway. Runway excursion is when a aircraft departs a runway in error.
"Scrambling" aircraft is referred to as an emergency take-off for fighter or close air support aircraft. It gives the launching aircraft runway priority over arriving or departing aircraft.
A runway
It is the aircraft carrier that has a runway called a flight deck.