Which of the following is known as fertilizer tree?

Correct option is C

Gliricidia is known as a “fertilizer tree” because it is used as green manure. It is a leguminous tree that can fix nitrogen from the atmosphere into the soil, improving soil fertility. Its foliage can be used as a natural fertilizer, and the tree is tolerant to pruning, making it a valuable resource in agroforestry systems.
Examine each option:
(a) Litchi: Incorrect; a fruit tree not typically used for green manure.
(b) Coconut: Incorrect; a fruit-bearing tree not known for green manure properties.
(c) Gliricidia: Correct; known for its role as a green manure and fertilizer tree due to its nitrogen-fixing capabilities.
(d) Guava: Incorrect; primarily a fruit tree, not used as green manure.
(e) Papaya: Incorrect; a fruit tree not used as a fertilizer tree.