The earliest texts on architecture is believed to be contained in:

Answer & Explanation

Answer: [A]

The earliest texts on architecture is believed to be contained in Sulva-sutras. Sulva-sutras, a collection of Hindu religious documents, were written between 600 and 300 B.C. Although this is quite a bit later than when the Vedas originate, the ideas set forth in them must have come from the earlier Vedic society. The four major Sulva Sutras, which are mathematically the most significant, are those composed by Baudhayana, Manava, Apastamba and Katyayana. Out of them the oldest belongs to Baudhayana and dates back to 600BC.