Option a is the correct answer. Raja Bhimdev II of solanki dynasty, who ascended the throne in 1178 CE, defeated Muhammad Ghori for the first time at the Battle of Kayadara in Mount Abu. This victory was significant as it thwarted Ghori's invasion of the Chaulukya kingdom of Gujrat ( solanki rajputs). Bhima II, along with his mother Naikidevi, played a crucial role in this triumph. In c.1195-97 CE, an army led by Aibak, Ghori's deputy, invaded again, but Bhima II defeated Aibak again and adorned himself as Abhinav Siddharaj.