Answer:
In order for medicine X to produce the effects that the researchers observed, it would most likely need to enter the nucleus of the targeted cells. The nucleus is where genetic material, such as DNA, is stored and where gene expression is regulated. Depending on the specific mechanism of action of medicine X, it may need to interact with or affect gene expression in some way in order to produce its observed effects. While the other organelles listed (Golgi apparatus, rough endoplasmic reticulum, and ribosomes) are important for various cellular functions, they are less likely to be directly involved in the mechanism of action of a medicine.