Scrutiny of returns allows tax authorities to seek explanations and, if unresolved, initiate assessment or enforcement. The proper officer may scrutinize a registered person's return and related particulars, notify discrepancies and seek an explanation; if the explanation is acceptable no further action is taken; if no satisfactory explanation is furnished within thirty days or the registrant fails to correct accepted discrepancies, the officer may initiate enforcement measures or proceed to determine tax and other dues.