Read the passage and answer the following question:

The tradition of erecting stupas may have been pre-Buddhist, but they came to be associated with Buddhism. Since they contained relics regarded as sacred, the entire stupa came to be venerated as an emblem of both the Buddha and Buddhism... Asoka distributed portions of Buddha's rehes to every important town and ordered the construction of stupas over them. By the 2nd century BCE, a number of stupas, including those at Bhuhut, Sanchi and Sarnath had been built.

By the end of which century a number of stupas had been built?

Second century B.C.E.

The correct answer is Option (3) → Second century B.C.E.

There were other places too that were regarded as sacred. This was because relics of the Buddha such as his bodily remains or objects used by him were buried there. These were mounds known as stupas. The tradition of erecting stupas may have been pre-Buddhist, but they came to be associated with Buddhism. Since they contained relics regarded as sacred, the entire stupa came to be venerated as an emblem of both the Buddha and Buddhism. According to a Buddhist text known as the Ashokavadana, Asoka distributed portions of the Buddha's relics to every important town and ordered the construction of stupas over them. By the second century BCE a number of stupas, including those at Bharhut, Sanchi and Sarnath had been built.

So, the correct option is [3].