WHERE TO SHOW GTA OUTWARD SUPPLY IN GSTR 3B

Respected Experts, Following is my query by way of example; I am GTA service provider. opted for 5% GST which is paid by service recipient under RCM. Now, my question is where to show this outward GTA supply in my GSTR-3B. Whether in Column 3.1 (a) or 3.1(c) ???. Please give your valuable remark on my above query.