The correct answer is option 2, Magadha. Magadha was the kingdom in ancient India that first used elephants in wars. Elephants were highly valued in warfare due to their size, strength, and intimidation factor. They were used as living tanks, capable of trampling enemies and causing chaos in enemy ranks. Magadha`s use of elephants in battle gave them a significant advantage over their enemies. This strategic advantage played a crucial role in Magadha`s military success and expansion of their kingdom. It is important to note that while the other options (Kosala, Champa, and Avanti) were also ancient kingdoms in India, there is no historical evidence that suggests they were the first to use elephants in wars.