Itr 4s and insurance commission agent !!! urgent

Dear Experts, My query is :- As per Section 44AD it is said that presumptive taxation rules are not applicable for person earning income by way of commission or brokerage. But when you open ITR 4S, U WILL FIND THERE ARE VARIOUS OPTIONS FOR NATURE OF BUSINESS AND THERE ALSO CONSISTS OPTION FOR GENERAL COMMISSION AGENTS TOO!! I request you all to please clarify why there is a difference between the act and ITR 4S and what does it signify?? Also, please clarify how to file return of person earning income from where TDS is deductible u/s 194D with the help of ITR 4/ 4S?? Thanks