Final answer:
Cells like the Leydig cells that synthesize significant amounts of steroid hormones predominantly contain an abundance of the smooth endoplasmic reticulum (SER), which is responsible for the production of these hormones.The correct option is 3.
Step-by-step explanation:
Cells that synthesize large amounts of steroid hormones, like testicular Leydig cells, would have an abundance of the smooth endoplasmic reticulum (SER). The SER is integral in the synthesis of lipids, including phospholipids, cholesterol, and steroid hormones, such as testosterone. Leydig cells, specifically, produce testosterone which is a steroid hormone that plays a critical role in male sexual development and function. Given that the SER is responsible for the production of lipids and steroid hormones, it is the organelle most abundant in cells like the Leydig cells that have high steroidogenesis activity.