Study the following type of secondary metabolite and select the correct option.
i) Terpenes: Made from mevalonic acid that is composed mainly of carbon and hydrogen.
ii) Phenolics: Extremely diverse class may also contain sulphur.

Terpenes are a large and diverse class of organic compounds, produced by a variety of plants, particularly conifers. They are derived from the mevalonic acid pathway and are composed mainly of carbon and hydrogen (isoprene units). Thus, statement i is correct.

Phenolics are an extremely diverse class of secondary metabolites that contain a hydroxyl group bonded directly to an aromatic hydrocarbon group. They are composed of carbon, hydrogen, and oxygen, but do not contain sulphur. Sulphur-containing secondary metabolites belong to a different class, such as glucosinolates. Thus, statement ii is incorrect.

Answer: i is only correct.