Firms Will Sometimes Choose to Operate at a Loss

Firms will sometimes choose to operate at a loss. Why?

A) Having sales revenue will contribute to variable costs which need to be paid even if no production takes place.
B) There may be fixed costs that need to be paid and producing something may be a way to minimise a loss.
C) A firm should always stop production if a loss is going to be made.
D) This is something that firms may do in the long run to cover fixed costs.