Answer: A. stores DNA
The nucleus is in charge of regulating and controlling all activities done within the cell. It carries the genes and structures containing important hereditary information. Being the most prominent and largest organelle in the cell, the main function of the nucleus is in housing the genetic material (DNA) needed by the cell to ensure cell division and inheritance. It is also a site of RNA or ribonucleic acid synthesis. RNA in turn assists in the production of ribosomes (protein factories of the cell).