The given passage focuses on two main points, Etiquette:
"Etiquette is the unwritten code that governs social behaviour.
Etiquette reflects formulas of conduct in which society or tradition
have invested."
and its relation with Culture:
"Etiquette is dependent on culture; what is excellent etiquette in
one society may shock in another. Etiquette can vary widely between
different cultures and nations."
Hence, the most appropriate title for this passage would be 'Etiquette and Culture'. So, option C is correct.
Option A: 'Etiquette' and 'manners' almost mean the same thing. Moreover, 'manners' is not mentioned in the passage.
Option B: 'Western Etiquette' is mentioned only in the beginning. The passage focuses more on etiquette in different cultures.
Option D: The 'Importance of Etiquette' is not the crux of this passage.
Hence options A, B and D are incorrect.