5.—The superintendent of the Gárda Síochána of the district in which the holder of a firearm certificate resides may at any time revoke such certificate if he is satisfied that the holder of such certificate—

( a ) has no good reason for requiring the firearm to which the certificate relates, or

( b ) is a person who cannot, without danger to the public safety or to the peace, be permitted to have a firearm in his possession, or

( c ) is a person who is declared by this Act to be disentitled to hold a firearm certificate, or

( d ) where the firearm certificate limits the purposes for which the firearm to which it relates may be used, is using such firearm for purposes not authorised by the certificate.