The correct answer is: B. Afghan style.
Sher Shah Suri’s tomb is a tomb complex located in Sasaram, Bihar, India. It was built by Sher Shah Suri, the founder of the Suri Empire, in 1545 AD. The tomb is a fine example of Afghan architecture. It is a square structure with a central chamber and four corner towers. The exterior of the tomb is decorated with intricate tile work and calligraphy. The interior of the tomb is decorated with marble and sandstone. The tomb is a UNESCO World Heritage Site.
The other options are incorrect. Option A is incorrect because Mughal architecture is a style of Islamic architecture that developed in the Mughal Empire in the 16th and 17th centuries. Option C is incorrect because Kachni architecture is a style of architecture that developed in the Kachwaha Rajput kingdom of Mewar in the 16th and 17th centuries. Option D is incorrect because Slave style is a style of architecture that developed in the Delhi Sultanate in the 13th and 14th centuries.