(a) in such a manner that it is not easily detachable;
(b) in an upright position or within 30 degrees of such position;
(c) in such a manner that each letter and figure thereon is clearly legible;
(d) in such a manner that the whole number plate is clearly visible;
(e) to the back of a motor cycle, motor tricycle, or trailer; and
(f) one to the back and one to the front of all other motor vehicles.