Answer: (4) Carotene

Explanation:

• Terpenes are a large class of natural organic compounds made up of isoprene units (C5H8). Carotenes are tetraterpenes composed of eight isoprene units (C40H56), making them a type of terpene.

• Chlorophyll is a chlorin pigment containing a porphyrin ring and a phytol side chain (which is a diterpene), but chlorophyll itself is not classified as a terpene.

• Lycopene is an acyclic carotenoid, which is a tetraterpene hydrocarbon similar to carotene; however, lycopene is often recognized as a carotenoid but structurally a terpene as well.

• Xanthophylls are oxygenated carotenoids (terpenoids) with oxygen-containing functional groups. Although related, they are classified as terpenoids rather than pure terpenes.

• Among the options, carotene is the clearest example of a terpene.

  Carotene is a classic example of a terpene found in plants. It belongs to the class of tetraterpenes built from eight isoprene units, playing essential roles in light absorption and photoprotection in photosynthesis along with other carotenoids like lycopene and xanthophylls.