SURKOTADA.
in SURKOTADA the citadel and lower town were joined together. They were fortified and now they have independent entrances in the south and also an intercommunicating gate.

**Answer:**

The correct answer is **option B) Surkotada**.

**1. Introduction:**
Kalibangan is an ancient archaeological site located in present-day Rajasthan, India. It was one of the major cities of the Indus Valley Civilization (also known as the Harappan Civilization) that flourished around 2500-1900 BCE. The city of Kalibangan was fortified, with both the citadel and the lower town being protected by fortifications.

**2. Citadel and Lower Town:**
In the ancient Indus Valley cities, the citadel and the lower town were two distinct areas of the settlement. The citadel was a raised platform or mound where the ruling elite, including the administrative and religious centers, resided. The lower town, on the other hand, was the residential and commercial area where the majority of the population lived.

**3. Fortifications at Kalibangan:**
At Kalibangan, both the citadel and the lower town were fortified, indicating the need for defense and protection. The fortifications were built to safeguard the inhabitants of the city from external threats and to maintain control over the resources and trade.

**4. Identification of the Fortification Location:**
According to archaeological evidence, the fortifications at Kalibangan were constructed using a combination of bricks and mud. The fortification walls enclosed the citadel and the lower town, providing a defensive barrier against potential attacks.

**5. Surkotada as the Correct Answer:**
The question asks for the place where both the citadel and the lower town were fortified at Kalibangan. Among the given options, Surkotada is the correct answer.

Surkotada is another archaeological site located in Gujarat, India. It is known for its fortified structures, including a citadel and a lower town. The fortifications at Surkotada are similar to those found at Kalibangan, with brick and mud walls enclosing the citadel and the lower town.

Therefore, the correct answer is **option B) Surkotada**, as it is the place where both the citadel and the lower town were fortified, similar to Kalibangan.