This question is A. The generation of new neurons in damaged areas of the brain.
Explanation
When a person suffers a wound in which one of their organs or tissues is affected, in general (depending on the severity of the injury) it is suggested to start a treatment/study with stem cells due to their ability to regenerate tissues. Additionally, they can also adopt the functions of all types of cells in the body such as neurons, pneumocytes, endothelial cells, sperm, red blood cells, among others. According to the above, when the brain suffers damage, it is necessary to apply a stem cell study. So the correct answer is A. The generation of new neurons in damaged areas of the brain.