(a) A licensee shall prominently and conspicuously display, in an area readily available and visible to the public, the original or a copy of the current license, whether permanent or temporary, at each licensed location, whether fixed or mobile. If a copy is displayed, the copy must be at least as large and as legible as the original license.(b) A licensee shall not display a license which is expired or has been revoked, after the licensee has been notified of the revocation of the license.(c) A licensee shall not display a license which has been altered in any substantive way.