Correct Answer: (c) Sanchi
Solution:From the perspective of architecture, the Stupa of Sanchi is considered as the best. Sanchi is located in Raisen district of Madhya Pradesh. This stupa was built by Ashoka. It is famous across the world for its stupas, monasteries, temples and pillars, which dated back to the 3ʳᵈ century B.C. The Stupa of Bharhut is situated in Satna district of Madhya Pradesh. Bharhut stupa was discovered by Alexander Cunningham. Amravati Stupa is located on the right bank of Krishna river in the Palnadu district of Andhra Pradesh. Colin Mackenzie traced this Stupa in 1797 A.D. Dhamekh Stupa of Sarnath (Varanasi) was built during the time of Ashoka, whose present form was built during the Gupta period. This stupa is designed on the flat surface without raising the base.