Answer the following question given this paragraph: 

Steroids (or sterols) have several functions. Sterols are a subgroup of steroids. The sterol cholesterol is an important part of cell membranes and plays other vital roles in the body. Cholesterol is a precursor to fat-soluble vitamins and steroid hormones. Steroid hormones include the male and female sex hormones. Sterols also have roles as second messengers in signalling pathways.


Q: Sterols are a subgroup of what?

 Choices:

- nuclides

- nutrients

- antibiotics

- steroids

A:
steroids
