The correct answer is: D. Vardhamana Mahavira.
Vardhamana Mahavira was the 24th Tirthankara, the last of the Jain Tirthankaras. He was born in Kundagrama, a village near Vaishali, in the Indian subcontinent, in the 6th century BCE. He renounced his royal life at the age of 30 and embarked on a life of asceticism. He attained Kaivalya (i.e., the supreme knowledge and final deliverance from the bonds of pleasure and pain) at the age of 42.
Rishabhanath was the first Tirthankara of the Jain tradition. He is said to have lived in the 9th Manvantara, and is credited with establishing the Jain religion.
Aristanemia was the second Tirthankara of the Jain tradition. He is said to have lived in the 10th Manvantara, and is credited with further developing the Jain religion.
Parsva Natha was the 23rd Tirthankara of the Jain tradition. He is said to have lived in the 8th century BCE, and is credited with reviving the Jain religion.
All three of these figures were important religious teachers who had a significant impact on the development of Jainism. However, it was Vardhamana Mahavira who attained Kaivalya, and is therefore considered to be the most important of the three.