The correct answer to this open question is the following.
Although there are no options attached we can say the following.
The decimal system and the development of the concept of zero are considered the greatest advancements of Indian mathematicians because thos concepts came to give mathematics a whole different meaning and a series of new possibilities to be applied in the field of mathematics with practical applications such as the numeral system, mathematical operations, measures, trade, among others.
Thousands of years before the Europeans could use it, the Indians had already discovered the zero and the decimals. This shows the intelligence and focus of the people in India. These concepts spread all over the Middle East and China before arriving in Europe.
The number system in India can be traced back to the sacred book called "The Vedas," approximately in 1200 BC.
