For the purposes of regulation 703(a)(ii), the openable part of the window in the wall—
(a) must be not less than 2·4m above the ground or paving immediately external to the window; or
(b) must be not less than 1·5m above the floor of the room containing the window; or
(c) must have a catch, bolt, lock or other stop located not less than 1·5m above the floor of the room containing the window so that the openable part of the window cannot be opened more than 125mm; or
(d) must have a securely fitted fly screen.