The correct answer is option 3: Lysosome.

Lysosomes are organelles found in mammalian cells that are rich in hydrolytic enzymes. These enzymes are responsible for breaking down different types of molecules, including proteins, nucleic acids, carbohydrates, and lipids.

Option 1: Mitochondria is incorrect because it is the organelle responsible for producing energy in the form of ATP through cellular respiration, and it does not contain a high concentration of hydrolytic enzymes.

Option 2: Ribosomes are incorrect because they are not organelles but rather small structures composed of RNA and protein. They play a role in protein synthesis but do not contain hydrolytic enzymes.

Option 4: Nucleus is incorrect because it is the organelle that contains the cell`s genetic material and is involved in controlling gene expression. It does not contain hydrolytic enzymes.

In summary, lysosomes are the organelles in mammalian cells that are rich in hydrolytic enzymes and are responsible for breaking down various molecules.