The ruins of the Sher Shah Suri Tomb are a fine example of Indo-Islamic architecture and are located in:

The correct answer is: b) Sasaram.

The Sher Shah Suri Tomb is a tomb located in Sasaram, Bihar, India. It was built in 1545 by Sher Shah Suri, the founder of the Suri dynasty, for his mother. The tomb is a fine example of Indo-Islamic architecture. It is made of red sandstone and has a square plan. The tomb is surrounded by a garden and a mosque.

The other options are incorrect. Patna is the capital of Bihar. Gaya is a city in Bihar that is known for its Buddhist pilgrimage sites. Bodh Gaya is a town in Bihar that is the site of the Mahabodhi Temple, a UNESCO World Heritage Site.