The correct answer is Chanakya.
Chanakya was a Brahmin scholar who played a key role in the establishment of the Mauryan Empire. He was the chief advisor to Chandragupta Maurya, the first emperor of the Mauryan Empire. Chanakya is also known as Kautilya or Vishnugupta. He was a brilliant strategist and economist. He is also the author of the Arthashastra, a treatise on statecraft and economics.
Brihadratha was the last Nanda king of Magadha. He was killed by Chandragupta Maurya in 321 BCE.
Ashoka was the third emperor of the Mauryan Empire. He is known for his Buddhist reforms and his military conquests.
Bindusara was the second emperor of the Mauryan Empire. He was the son of Chandragupta Maurya and Durdhara. He ruled from 321 BCE to 272 BCE.