Each handler shall maintain true and complete records of all inshell and shelled walnuts and walnut material, by categories, received, held, or disposed of by him. The records shall be maintained in such form as to permit verification of all transactions involved and shall be made available during normal business hours to authorized representatives of the Board or the Secretary of Agriculture. These records shall include the following:

(a) The names and addresses of the persons from whom received, and the quantities received from each such person;

(b) The names and addresses of the persons to whom disposal is made, and the quantities disposed of to each such person;

(c) The quantities used by the handler for such purposes as manufacturing, production of oil, and livestock feeding; and

(d) The quantities held on September 1, January 1, and April 1 of each marketing year.