Which is the correct definition of Normal Loss expectancy

Question $22$Select one:

a$.$

The dollar loss expected when a critical part of the protection system, such as an automatic sprinkler, is out of service or ineffective

b$.$

The dollar loss expected when all private and public protection systems are inoperative or ineffective.

c$.$

The dollar loss expected when none of the private protection systems are functioning. The fire in this case would probably burn until stopped by a fire wall, until it burns all its fuel, or until the public fire department summoned by an outsider, arrives.

d$.$

The dollar loss expected when both private and public protection systems are operative.