Cisternae are flattened membrane sacs in the Golgi apparatus

Steps:

• Define cisternae as stacked, flattened membrane-bound sacs in eukaryotic cells.
• Recall that the Golgi apparatus is defined by its cisternae for processing and packaging.
• Evaluate each option against this definition.
• Select the match based on standard cell biology.

Why C is correct:

• The Golgi body consists of 4–8 stacked cisternae that modify, sort, and package proteins and lipids.

Why the others are wrong:

• A. Chloroplasts have thylakoid membranes in grana stacks, not true cisternae.
• B. Endoplasmic reticulum forms interconnected tubules and sacs, but not stacked cisternae.
• D. Mitochondria contain cristae as inner membrane folds, distinct from cisternae.

Final answer: C