Section 44AA of Income Tax Act- ITR Defective notice u/s 139(9)

I am a Partner in CA Partnership firm and I filled ITR 3 for A.Y. 2020-21. I received a notice from IT dept. that my return is defective stating that "Taxpayer is offering Income under the head Profits and gains from Business or Profession. Hence, as per the provisions of Sec.44AA, the taxpayer is required to maintain books of accounts. However, as seen from the return, the taxpayer has not filled up Part A of the Profit and Loss Account and Balance Sheet. Further, income from business has not been offered under presumptive taxation, if eligible". 

Kindly give your suggestion whether I am supposed to maintain books of account u/s 44AA, my annual income is less than Rs.25 lakhs. Whether Partner of CA partnership firm required to maintain books of account.

Regards