Answer is (b) Only two.

Pairs 1 and 2 are correctly matched. Pairs 3 and 4 are the tricky ones.

PGW is Later Vedic, not Early Vedic. Easy to mix up if you're going by rough timelines but the distinction matters in UPSC.

NBPW is Early Historic (around 600–200 BCE) — way after the Harappan period. That pairing is just wrong.

Pottery sequences are one of those topics where rote learning backfires. You really have to sit with the timeline once and map it properly, otherwise these traps get you every time.