Explanation
Why Correct: The core Vedic literature, including the four Vedas (Rig, Sama, Yajur, Atharva), was composed orally between approximately 1500 BCE and 1000 BCE, corresponding to the Early Vedic or Rigvedic period.
Distractor Analysis: 1000 BCE is only the end date, not the full period. 3000–2500 BCE predates the Vedic period and aligns with the Indus Valley Civilization; the Gupta Empire (c. 319–550 CE) is much later. 1200–1000 BCE is a narrower, later sub-period within the broader composition timeline.
Takeaway: The later Vedic texts (Brahmanas, Aranyakas, Upanishads) were composed from about 1000 BCE to 500 BCE, marking the transition to the Later Vedic period.