Terpenoids are a large and diverse class of naturally occurring organic compounds derived from isoprene units. These units are linked together in various configurations to form different types of terpenoids, such as monoterpenes, diterpenes, and sesquiterpenes. Therefore, the correct answer is (C).
- Option (A) is incorrect because terpenoids are not made from amino acids.
- Option (B) is incorrect because carbohydrates are not the building blocks of terpenoids.
- Option (D) is incorrect because triacylglycerol is a type of lipid, not related to terpenoid synthesis.
Thus, the correct answer is (C).