Option 1: Jute is the correct answer. Jute is a natural fiber that is commonly used for making brown paper. It is known for its strength, durability, and affordability, which makes it suitable for packaging materials like brown paper bags. Jute fibers are brown in color, and when processed, they are often used to create the characteristic brown paper that is commonly referred to as "brown paper."

Option 2: Cotton is not called "brown paper." While cotton is also used in the production of paper, it is not specifically known as "brown paper."

Option 3: Rubber is not called "brown paper." Rubber is a material derived from the sap of rubber trees, and it is not used to make paper.

Option 4: Tea is not called "brown paper." Tea is a beverage that is made from the leaves of the Camellia sinensis plant and has no relation to the term "brown paper."

Overall, the correct answer is option 1, jute.