The name of the Indian Astronomer (who knew five astronomical systems), who lived in the 6th century was

Answer: Option A

Vārāhamihira (c. early 6th-century), also called Vārāha or Mihira, was a Hindu polymath who lived in Ujjain (Madhya Pradesh, India). He was born in the Avanti region, roughly corresponding to modern-day Malwa, to Adityadasa, who was himself an astronomer.