(1) Satisfactory proof of experience may include but is not limited to:

(a) valid copies of W-2 or 1099 tax forms verifying employment;

(b) valid copies of form 1120 corporate tax returns signed by the broker or manager as owner of the business; or

(c) signed letters from a lender on the lender's letterhead verifying that the broker has competently originated loans for the required time period.