Manava Dharmashastra 3.23

3.23

ṣaḍ ānupūrvyā viprasya kṣatrasya caturo 'varān
viṭśūdrayos tu tān eva vidyād dharmyān //

One may know that the first six according to the order (followed above) are lawful for a Brahmana, the four last for a Kshatriya, and the same four, excepting the Rakshasa rite, for a Vaisya and a Sudra.