_______ are known as the powerhouse of the cell.

Correct option is A

The correct answer is (a) Mitochondria.

Mitochondria are organelles found in the cells of most eukaryotes, such as animals, plants, and fungi. They are responsible for producing most of the energy a cell needs to function, and are especially important in organs that require a lot of energy, like the heart, liver, muscles, and brain

Information Booster:

• Cytoplasm is the gelatinous liquid that fills the inside of a cell. It is composed of water, salts, and various organic molecules. Some intracellular organelles, such the nucleus and mitochondria, are enclosed by membranes that separate them from the cytoplasm.
• The endoplasmic reticulum (ER) serves important functions particularly in the synthesis, folding, modification, and transport of proteins.
• A nucleus, as related to genomics, is the membrane-enclosed organelle within a cell that contains the chromosomes. An array of holes, or pores, in thenuclear membraneallows for the selective passage of certain molecules (such as proteins and nucleic acids) into and out of the nucleus.