An Ill or Injured Patient May Have Suffered from Damaged

An ill or injured patient may have suffered from damaged tissues that the cell cycle,including mitosis,won't naturally repair or replace.This may include damaged nerves,or skin,or muscle.A form of biotechnology that attempts to stimulate new cell divisions with application of cells that are genetically unspecialized,is 

A) stem cell research.
B) cloning.
C) preimplantation genetic diagnosis.
D) DNA profiling.
E) genetic engineering.