The Gayatri mantra, one of the most revered Vedic mantras, is originally from which of the following…

The Gayatri mantra comes from the Rigveda (Mandala 3, hymn 62, verse 10). It is a prayer to Savitr, the sun as the giver of light and inspiration, attributed to the sage Vishvamitra and composed in the gayatri metre that gives it its name. Later texts such as some Upanishads quote and comment on it, and the Samaveda and Yajurveda repeat the verse for chanting and ritual, but its original place is the Rigveda; the Aitareya Brahmana is a prose ritual commentary attached to the Rigveda, not where the hymn first appears.