The correct answer is A. Vigraharaj-IV.
Vigrahamalla, also known as Vigraharaj-IV, was the Chauhan ruler of Ajmer from 1150 to 1167 CE. He was a powerful ruler who expanded the Chauhan kingdom to include Delhi and Hansi. He was also a patron of the arts and literature.
Ajayraj was the Chauhan ruler of Ajmer from 1138 to 1150 CE. He was a weak ruler who was unable to prevent the expansion of the Delhi Sultanate.
Arnoraj was the Chauhan ruler of Ajmer from 1167 to 1173 CE. He was a short-lived ruler who was unable to maintain the power of the Chauhan kingdom.
Vigrahapala was the Chauhan ruler of Ajmer from 1173 to 1178 CE. He was a weak ruler who was unable to prevent the decline of the Chauhan kingdom.