its a tricky question if it would have been soo easy oak wouldn't ask this question so I exclude b lets talk about
A its candida a fungus I can't imagine a fungus in such a child so it out.
B is already out so it gone case
C Neisseria no it can't no sexual history I mean child abuse becasue it says normal child that mean there is no chance of having this organism
D its a normal flora of the body
E streptococcus predominantly in the oral cavity/gingiva although 15-20% of women harbour this organism during productive age.
so i will have to pick from D & E since D is more common in reproductive age I would go for D
