6. A natural child who is a minor may be adopted only in the following cases:(a) with the consent of the father and mother if they both actually assume the care, maintenance or education of the child; otherwise with the consent of that parent who actually assumes his care, maintenance or education, or with the consent of either in other cases;
(b) when the care, maintenance or education of the child has not actually been assumed by the father or mother or any other ascendant of such child for at least six months before such child was placed for adoption;
(c) when the Superior Court has declared the father and mother totally deprived of parental authority.