E-filing mandatory if income more than 10 lacs

CA. Shwetank Vats (Chartered Accountant)     22 July 2012

The finance ministry has made it mandatory for people who have an annual income of over Rs. 10 lakh to file their tax returns for 2011-12 electronically.

My Q is :-
(a)10 Lacs is Gross Total Income
   (Column B4 of ITR-1)
             OR
(b)10 Lacs is Total Taxable Income (Assessment Income on which tax shall be calculated) (i.e. Gross Total Income Less Deduction u/s 80) (Column 15 of ITR-1)

Which should be read more than 10 Lacs either (a) Or (b) as above

Please reply urgently