The right answer that fills the blank is: smooth endoplasmic reticulum. There are two kinds of endoplasmic reticulum, the smooth one and the rough.
Both have some special functions within the cells. For example, the rough endoplasmic reticulum is specialized in making proteins for the body, it can do other things too, but this is its main function. Now let's talk about the liver cells, they're specialized in detoxifying drugs and alcohol right? The question gave us this information, and with that, we can be sure of the answer because, one of the main things that the smooth endoplasmic reticulum does is to detoxify these kinds of things, this happens because it has the metabolism of some carbohydrates according to some studies.