The correct answer is B. Surkotada.
The remains of a horse have been found at the Indus site of Surkotada. This discovery suggests that the Indus people were familiar with horses and may have used them for transportation or warfare.
Lothal is an Indus site located in Gujarat, India. It is known for its well-preserved dockyard and other urban features. However, no remains of horses have been found at Lothal.
Kalibangan is an Indus site located in Rajasthan, India. It is known for its large fortifications and other urban features. However, no remains of horses have been found at Kalibangan.
Banawali is an Indus site located in Haryana, India. It is known for its large granary and other urban features. However, no remains of horses have been found at Banawali.
The discovery of horse remains at Surkotada is significant because it provides evidence that the Indus people were familiar with horses. This suggests that the Indus people may have used horses for transportation or warfare. The discovery of horse remains at Surkotada also provides evidence that the Indus people were connected to other cultures that used horses, such as the Central Asian steppe cultures.