What term describes the pan-Arab practice of alternating between a local dialect and Modern Standard Arabic depending on the social context?

• A Code-switching
• B Bilingualism
• C Diglossia ✓
• D Pidginization

Diglossia refers to the stable coexistence of two varieties of the same language — in Arab societies, the 'high' variety (Modern Standard Arabic) is used in writing, news, and formal speech, while the 'low' variety (colloquial dialects like Masri) is used in daily conversation.