When completing Form T2125, Statement of Business or Professional Activities, you have to enter an industry code that corresponds to your main business activity.
If more than one code corresponds to your business, or if your business has more than one activity, use the code thatmost closely describes your main business activity.
http://www.cra-arc.gc.ca/tx/bsnss/tpcs/slprtnr/rprtng/ndstry/menu-eng.html
