Every culture has certain rules that govern which emotions may be expressed, under what circumstances, and how, and these rules are called

A) sentiment rules.
B) display rules.
C) narcissist rules.
D) operational rules.

The rules that govern which emotions may be expressed, under what circumstances, and how are called "display rules." Sentiment rules refer to the norms about which emotions are appropriate to feel, whereas narcissist rules and operational rules are not relevant to this context.