Answer:
B. Developed advanced medical treatments
Explanation:
I'll use process of elimination here.
The Gupta had less land than the Mauryan Empire did, so A is out.
Both Buddhism (Late 6th century BCE) and Hinduism (1750 BCE?) were formed well before the Gupta Empire came to rise, so C is also out.
The Gupta had trade relations with a good amount of countries, including the Byzantine Empire, so D is also out.
This leaves B, which is true. Gupta doctors used mercury and iron, alongside using herbs for healing.
