Introduction:
A fiber crop is a plant that is cultivated primarily for the fibers it produces, which are used in various industries such as textile, paper, and rope manufacturing. These crops have long, strong, and durable fibers that can be spun into yarn or used directly in different applications. Among the given options, cotton is the correct answer as it is one of the most widely cultivated fiber crops in the world.

Explanation:
Cotton:
- Cotton is a natural fiber crop that is derived from the cotton plant, scientifically known as Gossypium.
- It is cultivated for its soft and fluffy fibers that grow in protective capsules known as bolls.
- These fibers are composed mainly of cellulose and are spun into yarn or thread to produce textiles.
- Cotton fibers have desirable properties such as strength, moisture absorption, and breathability, making them ideal for clothing, bedding, and various other textile applications.

Other options:
- Sugarcane: Sugarcane is primarily grown for its high sugar content and is used in the production of sugar, molasses, and ethanol. It does not produce fibers suitable for textile applications.
- Tea: Tea is an aromatic beverage made from the leaves of the Camellia sinensis plant. While tea leaves have certain fibrous components, they are not cultivated primarily for their fibers.
- Rubber: Rubber is obtained from the latex of rubber trees and is primarily used in the production of various rubber products. It does not produce fibers suitable for textile applications.

Conclusion:
In conclusion, cotton is the correct answer as it is a widely cultivated fiber crop known for its soft and durable fibers. The other options provided, such as sugarcane, tea, and rubber, are not fiber crops and are primarily used for different purposes.

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