The answer is a) cancer.
Cells must control mitosis (cell division) in order to maintain normal cell function. If something happens to the control of mitosis, the healthy cells will divide uncontrollably. These new cells are cancer cells and they are also out of control. They will continue to divide uncontrollably, so the mass of the cancer cells will grow.
Regarding other choices:
- cystic fibrosis is an inherited disorder of lungs and digestive system,
- albinism is a congenital disorder characterised by the absence of pigment in the skin and hair,
- meiosis is cell division resulting in the reduction of a chromosome number in half.