The correct answer is A. Nucleus.
The nucleus is the control center of the cell. It contains the cell’s DNA, which is the blueprint for the cell’s structure and function. The nucleus also contains the nucleolus, which is responsible for the production of ribosomes. Ribosomes are the organelles that are responsible for protein synthesis.
The cytoplasm is the jelly-like substance that fills the cell. It contains many different organelles, including the mitochondria, the endoplasmic reticulum, and the Golgi apparatus. The cytoplasm is also where the cell’s chemical reactions take place.
The cell membrane is the outer layer of the cell. It protects the cell from the environment and allows nutrients and waste products to enter and exit the cell.
The endoplasmic reticulum is a network of tubules and sacs that is found in the cytoplasm. It is responsible for the production of proteins and lipids.
The Golgi apparatus is a stack of flattened sacs that is found in the cytoplasm. It is responsible for packaging and distributing proteins and lipids.