(a) The regulatory authority may require an annual report from each utility company of all its expenditures for business gifts and entertainment and institutional, consumption-inducing, and other advertising or public relations expenses.
(b) The regulatory authority shall not allow as costs or expenses for ratemaking purposes any of the expenditures that the regulatory authority determines not to be in the public interest. The cost of legislative advocacy expenses shall not in any case be allowed as costs or expenses for ratemaking purposes.
(c) Reasonable charitable or civic contributions may be allowed not to exceed the amount approved by the regulatory authority.