The correct answer is A. Rishabhanath and Mahavira.
The Rig Veda is one of the four sacred texts of Hinduism. It is a collection of Vedic Sanskrit hymns, and is one of the oldest scriptures of any Indo-European language. The Rig Veda is believed to have been composed between 1500 and 1200 BCE.
The Rig Veda contains references to several Jain tirthankaras, including Rishabhanath and Mahavira. Rishabhanath is the first tirthankara of the Jain tradition, and is believed to have lived around 900 BCE. Mahavira is the 24th tirthankara of the Jain tradition, and is believed to have lived around 599-527 BCE.
The Rig Veda also contains references to other Jain concepts, such as karma and moksha. Karma is the law of cause and effect, and moksha is the state of liberation from the cycle of rebirth.
The Rig Veda is an important text for both Jains and Hindus. It provides insights into the early history of Jainism, and its teachings on karma and moksha.
The other options are incorrect because they do not list the two Jain tirthankaras who find mention in the Rig Veda.