Whoever, being a public servant, legally bound as such public servant to apprehend or to keep in confinement any person under sentence of a Court for any offence or lawfully committed to custody, intentionally omits to apprehend such person, or intentionally suffers such person to escape or intentionally aids such person in escaping or attempting to escape from such confinement, shall be punished,—

   (a)  with imprisonment for life or with imprisonment of either description for a term which may extend to fourteen years, with or without fine, if the person in confinement, or who ought to have been apprehended, is under sentence of death; or

   (b)  with imprisonment of either description for a term which may extend to seven years, with or without fine, if the person in confinement or who ought to have been apprehended, is subject, by a sentence of a Court, or by virtue of a commutation of such sentence, to imprisonment for life or imprisonment for a term of ten years, or upwards; or

   (c)  with imprisonment of either description for a term which may extend to three years, or with fine, or with both, if the person in confinement or who ought to have been apprehended, is subject by a sentence of a Court to imprisonment for a term not extending to ten years or if the person was lawfully committed to custody.