The following sentences describe one of the sites of the Harappan civi

The following sentences describe one of the sites of the Harappan civilization:
‘The settlement is divided into two sections, one smaller but higher and the other much larger but lower. Archaeologists designate these as the Citadel and the lower town respectively. Both were walled. Several buildings were built on platforms, which served as foundations.’
Which of the following sites does it refer to ?

Harappa
Mohenjodaro
Lothal
Kalibangan
This question was previously asked in
UPSC CAPF – 2011
The description of the settlement divided into a smaller, higher Citadel and a larger, lower town is characteristic of many major Harappan sites like Harappa, Mohenjo-daro, and Kalibangan. However, the phrase “Both were walled” is particularly applicable to Kalibangan. While the Citadels at Harappa and Mohenjo-daro were walled, their Lower Towns were not consistently or completely walled. At Kalibangan, both the Citadel (which was further divided into two parts) and the Lower Town were enclosed by fortification walls. The construction of buildings on platforms is also a common feature across these sites to protect them from floods or provide stable foundations.
– Major Harappan cities often had a bipartite division into a Citadel and a Lower Town.
– The Citadel was typically located in the western part, higher, and smaller, while the Lower Town was larger and located in the eastern part.
– The key distinguishing feature mentioned here is that *both* sections were walled.
– Kalibangan is known for having fortification walls around both the Citadel and the Lower Town.
Other sites like Lothal have a different layout, typically a single walled area divided into functional sectors. The presence of a citadel and lower town, particularly with fortification around both, is a specific architectural feature helpful in identifying the site.