The correct answer is - option D.
Explanation:
When an individual takes drugs such as heroin, nicotine, cocaine and methamphetamine increases or promotes the neurochemical reaction that increases the amount of dopamine which is a primary factor in addiction that is secreted by neurons in the brain's reward center.
Higher dopamine levels lead to pleasure in the mind of an addict and it makes people forget the pain or stress and gives immense pleasure.
Thus, the correct answer is - option D.
Explanation:
missense
silent
nonsense
frameshift ( delition + insertion)
insertion,delition