The organelle involved in packaging and trafficking of cellular products is the:

The Golgi apparatus is the correct answer because it plays a crucial role in modifying, sorting, and packaging proteins and lipids that are synthesized in the cell. Once these macromolecules are produced in the rough endoplasmic reticulum, they are transported to the Golgi apparatus, where they undergo further processing. The Golgi apparatus then directs these cellular products to their specific destinations, either within the cell or for secretion outside the cell. This organelle can be thought of as the cell's postal service, ensuring that the materials it produces are sent to the right places in the appropriate forms.

In contrast, the nucleus is primarily involved in storing genetic information and coordinating activities such as growth, metabolism, and reproduction. Mitochondria are responsible for energy production through oxidative phosphorylation, while the rough endoplasmic reticulum is mainly involved in the synthesis of proteins destined for export, but it does not perform the packaging and trafficking functions that the Golgi apparatus does.