The inner core of silk filament, fibrion is a/an

✅ Explanation: The inner core of a silk filament, called the fibrion, is primarily composed of the protein fibroin. Fibroin is a strong, fibrous protein that gives silk its strength and elasticity.

📌 Other Options Explanations:
-(b) Amino acid: Amino acids are the building blocks of proteins.
-(c) Carbohydrate: Carbohydrates are energy sources and structural components in organisms.
-(d) Lipid: Lipids are fats and oils, which play various roles in organisms.