SALARY/F&O Audit

1. Loss from trading in futures and options will be considered as a normal business loss and it will have the same treatment as contemplated under sec 72 
2. As per sec 71 relating to inter head adjustments loss under the head F&O can be set it off against any income other than Salary. 
3. With respect to T.O for F&O premium received on sale of options, positive and negative differences and in respect of reverse trade, differences shall form part of T.O of F&O business. (For a detailed explanation see for further clarification on F&O's T.O) 
4. In your case, ITR 3 or ITR-4 (opted to Sec 44AD) can be filed.
5. Whether tax audit applicable or not depends on the T.O limit for the current year. However, the loss will not be a relevant consideration u/s 44AB, T.O should be computed by taking all the above incomes (point 3) and see whether it crosses Rs. 1 crore. If it does, Tax audit will be applicable. 
6. It is prudent to show the correct figures in the IT return. And it would be advisable to show your F&O loss in your return as it will be beneficial for you to set off the same in the future years. 
Please correct me if the above solution has an alternative view.