The facial muscles which control our ability to produce a set of standard expressions
-
5
-
6
-
7
-
8
Research has identified 5 basic facial expressions that are universally recognized across cultures: happiness, sadness, anger, fear, and disgust. Some researchers later added surprise as a sixth category, but the classic model identifies 5 core expressions controlled by specific facial muscle groups. The question appears to refer to this established framework of basic emotional expressions.
The widely circulated trivia statement is: 'A core set of five facial muscles control our ability to produce a set of standard expressions which convey anger, happiness, surprise, fear, sadness and disgust.' That is the source of this question, and the answer it expects is 5. It is true that the face has ~43 muscles capable of thousands of expressions, but the specific factoid this item is drawn from cites a core set of five muscles for the standard/basic expressions. So the DB's marked answer (5) matches the intended source. This is soft trivia rather than a rigorous anatomical constant, but relative to the given options (5/6/7/8), 5 is the correct keyed answer.