The answer is C. During the Gupta period (3rd century CE to 590 CE), Indian mathematicians developed both the modern decimal-based place notation and the concept of zero. It was especially the mathematical text "Bakshali manuscript," from the Gupta period, which is known as the earliest Indian mathematical textbook containing the use of a zero symbol and the modern decimal system.
These mathematical developments were later adopted by Muslim scholars, who made important advancements in the field of algebra and centuries later, thanks to commercial links in the Mediterranean, it entered in Europe. Fibonacci, in the 13th century, was the first Western mathematician that used the zero symbol and the decimal system which was much more efficient than the old Roman numerals.