Explanation:

• Statement 1 is incorrect: The inception of Sanchi as a sacred centre is attributed to the Mauryan emperor Asoka. His reign in the 3rd century BCE is considered instrumental to the spread of Buddhism throughout the Indian subcontinent.

• With the establishment of the monolithic Asoka Stambha (pillar) bearing a highly elaborate capital, Emperor Asoka distinguished Sanchi as a site of great importance.

• Contemporary with the stambha was a brick stupa, which was later increased in scale during the Sunga dynasty (184-72 BCE), covered with an ashlar stone veneer, and augmented with circumambulatory paths and staircases with ornate balustrades, harmika, yashti, chhatra, and four torana, which were later ornamented during the Satavahanas dynasty in the 1st century CE.

• Statement 2 is incorrect: Amaravati Stupa is considered to be one of the largest in Andhra Pradesh and is also sometimes compared to the Sanchi Stupa. With a height of 27 m and a diameter of 50 m, the monument has a circular vedika built with bricks and protruding rectangular Ayaka platforms for the four directions.

• Statement 3 is correct: Begums of Bhopal made a great contribution to the preservation of the Stupa of Sanchi. Following are the major contributions made by them.

• Shahejahan Begum and her successor Sultan Jahan Begum of Bhopal were the rulers of Bhopal who made generous grants for the preservation of the Stupa of Sanchi.

• A museum was built near the stupa and it was built mainly on the financial support of Begum Sultan Jahan Begum.

Hence option 1st is correct.