Return scrutiny: officer may require explanations and initiate assessment or enforcement if discrepancies remain unresolved. The proper officer may scrutinize a registered person's return and related particulars to verify correctness, notify observed discrepancies and seek explanations; if the explanation is acceptable, no further action follows, but if not satisfactorily explained within the prescribed period or if accepted discrepancies are not corrected, the officer may initiate administrative or enforcement actions or proceed to determine tax and other dues under the statutory determination procedures.