In case, after accepting the discrepancies, no satisfactory explanation is furnished within a period of thirty days or such further period as may be permitted, proper officer may:
(a) Initiate Audit of accounts by the tax authorities under Section 65; or
(b) Initiate special audit under Section 66; or
(c) Initiate inspection, search and seizure under Section 67; or
(d) proceed to determine the tax and other dues under Section 73 or Section 74.
(ICAI FAQ PUBLICATIONS 06-09-2017 SCRUTINY OF RETURNS: FAQ NO. 14)