Which of the following is not a Dosha mentioned in the Veda?

Rajas

"Rajas" is not a Dosha mentioned in the Vedas. In Ayurveda, an ancient system of medicine that originated in the Vedic texts, the three primary doshas are Vata, Pitta, and Kapha. "Rajas" is a term more commonly associated with the Gunas, which represent the qualities of nature in Hindu philosophy, but it is not specifically a dosha in Ayurveda.