The correct answer to this open question is the following.
Although there are no options attached, we can say the following.
The proof that historians have of how medicine was practiced in the Gupta Empire is that these historians found that the Gupta Empire people knew about chemistry and also knew how to use it effectively.
Susrutha Samhita was one of the sources or treatises recorded in Indian history that explained medicine with the use of plants and roots to heal people during the Gupta Empire in India. It specialized in surgery.
The other important document was called the Charaka Samhita, which explains the logic behind the use of natural medicine as a method for healing.
