T.R. Malthus wrote

Options

A. An Essay on Population
B. Origin of Species
C. Discovery of India
D. Text Book of Mathematics

Explanation

**Step-by-Step Solution:**

1. **Identify the Full Name of T.R. Malthus**: T.R. Malthus is an abbreviation for Thomas Robert Malthus. This is important to know as it provides context to his contributions.

2. **Recognize His Profession**: T.R. Malthus was an English scholar and economist. Understanding his background helps in comprehending the significance of his work.

3. **Highlight His Major Work**: Malthus is best known for writing "An Essay on the Principle of Population." This essay discusses the relationship between population growth and resources, particularly food supply.

4. **Select the Correct Answer**: Based on the information provided, the correct answer to the question "T.R. Malthus wrote" is "An Essay on Population."

5. **Review Other Options**: The other options mentioned (such as a textbook of mathematics) are not related to Malthus's work, confirming that the essay on population is indeed his significant contribution.

**Final Answer**: T.R. Malthus wrote "An Essay on Population."

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