- The Golgi apparatus is a critical organelle in eukaryotic cells primarily responsible for the modification, sorting, and packaging of proteins received from the rough endoplasmic reticulum (ER).
- After proteins are synthesized in the rough ER, they are transported to the Golgi apparatus where they undergo further post-translational modifications such as glycosylation and phosphorylation.
- Additionally, the Golgi apparatus sorts these proteins and packages them into vesicles for delivery to their specific cellular destinations, including secretion outside the cell or incorporation into the plasma membrane.

To clarify the other options:
- Option 2 (Synthesis of ribosomal RNA) occurs in the nucleolus, not the Golgi apparatus.
- Option 3 (Energy production through ATP synthesis) mainly takes place in the mitochondria.
- Option 4 (Intracellular digestion of macromolecules) is the role of lysosomes.

Thus, the best description of the primary role of the Golgi apparatus is protein modification and packaging.