The question asks to identify the first mathematician who accurately calculated the value of pi ($\pi$).
Aryabhatta I, a prominent Indian mathematician and astronomer, is credited with providing one of the earliest accurate approximations of pi ($\pi$).
In his work, Aryabhatiya (written around 499 CE), he stated the value of pi ($\pi$) as approximately 3.1416. He described this value using the word 'asanna' (meaning 'nearly') and calculated it by considering the circumference and diameter of a circle.
While earlier civilizations had approximations for pi, Aryabhatta I's calculation was notably precise for its time and represented a significant advancement.
Therefore, Aryabhatta I was the first mathematician to calculate the correct value of pi ($\pi$) within the context of the provided options and historical significance.