Explanations:India Gate is a significant war memorial located in New Delhi, India. It was built in memory of the Indian soldiers who died in World War I and the Third Anglo-Afghan War. The monument is a prominent landmark and a popular tourist destination, making it a famous monument in Delhi. This statement is true and is included in the correct answer.
The second statement claims that the silk Karhana in Delhi had more than 40,000 workers. This statement is not accurate. The silk Karhana, which refers to a silk factory or industry, does not have such a large workforce. This statement is false and is not included in the correct answer.
The third statement asserts that Delhi is the biggest city in India. This statement is true based on population statistics. Delhi is the most populous city in India, with a population of over 29 million people, making it the largest city in the country. This statement is true and is included in the correct answer.
Therefore, the correct answer is option D, which includes the true statements about India Gate being a famous monument in Delhi and Delhi being the largest city in India. The statement about the silk Karhana having more than 40,000 workers is not accurate and is not included in the correct answer.