Platforms with 'Ayaka pillars' (five pillars on raised platforms at the four cardinal points) are a distinctive feature of the:

The "ayaka" (aryaka) platforms with pillars are a distinctive feature of the stupas of the Andhra region, especially the great stupa at Amaravati.

About ayaka platforms:

• They are rectangular platforms projecting from the base of the stupa drum, at the four cardinal directions (east, west, north and south).
• On each platform stood five tall pillars, called "ayaka khambhas" (ayaka pillars).
• The five pillars are believed to represent the five great events of the Buddha's life: birth, renunciation, enlightenment, first sermon and death (mahaparinirvana).
• The platforms were decorated with carved panels.
• This feature is typical of the Andhra stupas, such as Amaravati, Nagarjunakonda, Jaggayyapeta and Ghantasala.

About the Amaravati stupa:

• It is located at Amaravati, on the south bank of the Krishna river, in the Palnadu (earlier Guntur) district of Andhra Pradesh.
• The ancient site was called "Dhanyakataka".
• It was built in stages from about the 3rd century BCE to the 3rd century CE.
• It was decorated with exquisite carved panels of white-green limestone, showing scenes from the life of the Buddha and the Jatakas.
• These panels are among the finest works of the "Amaravati school" of art, known for slender, graceful figures in lively poses.
• Much of the stupa was destroyed in the 18th and 19th centuries, when local people used its stones for building.
• Many of its sculptures are now in the British Museum (London) and the Government Museum, Chennai.
• NCERT discusses how many of the sculptures were removed and taken to different places, unlike Sanchi, which survived in its original setting.

Other Andhra stupas:

• Nagarjunakonda: a great Buddhist centre under the Ikshvakus.
• Bhattiprolu: an early stupa with an inscribed relic casket.

Why not the other options?

• ✗The Sanchi stupa is famous for its four carved gateways (toranas).
• ✗The Bharhut stupa is famous for its carved railings.
• ✗The Dhamek stupa is at Sarnath.