Which of the following is an important source for the Later Vedic period?

The Later Vedic period is reconstructed from the Samaveda, Yajurveda, Atharvaveda, Brahmanas, Aranyakas and early Upanishads. Among the given choices, the Yajurveda is the correct direct source; Buddhist texts belong mainly to a later setting and the choices using ‘only’ are too restrictive. Therefore, the remaining options do not match the precise term, source, institution or chronological context asked in the question. Yajurveda fits that evidence because it matches the specific chronology, agency and function contained in the question. A comparison with the alternatives is useful: Buddhist texts, Only the Puranas and Only the Rigveda are genuine historical terms or names, but each belongs to a different office, patron, text, region or sequence. Reading the question as a relationship among person, period, place and institutional purpose prevents that mistake. The supporting source also helps separate later textbook shorthand from the more precise historical formulation. The compact memory link is therefore Yajurveda together with the factual context above, not the isolated option letter.