Step 1: Identify relevant coconut product.
Coconut husk is fibrous and processes into cocopeat. Cocopeat serves as a common medium in nurseries for seed germination and plant growth.
Step 2: Rule out incorrect options.
- Mat → Irrelevant to nursery applications.
- Liquid nutrient → Not directly produced from husk.
- Oil → Originates from copra (dried endosperm), not husk.
Step 3: Determine the correct answer.
Cocopeat is the correct selection.
Final Answer: \[\boxed{\text{Cocopeat is obtained from coconut husk and used in nurseries.}}\]