Answer:
A; in vitro observation
Explanation:
In-vitro is a process in which an experiment/organism is performed/taking place in a test tube or culture dish (controlled environment) outside of a living organism. Since a specific molecule was taken from the yeast cell and placed in a separate environment outside of its original living organism (the yeast cell), it is under in-vitro observation. A good example of in-vitro observation is IVF (in-vitro fertilization), when an egg from a mother and the sperm from a father fertilizes in a test tube outside of the mother's body and conception happens outside the body in a laboratory until it becomes an embryo and is placed back into the mother's body.