If the blood group of both the parents is $O^{+ve}$, the probable blood group of the child is

The correct option is C $O^{+ve}$ and $O^{-ve}$
The blood group of an individual is dependent on the presence of antigens in the red blood cells and the Rh factor which are inherited from the parents. If both the parents are O- positive, they might contain recessive negative gene in their DNA which on combining with another negative gene can give rise to a child with a negative gene. As per the inheritance patterns of blood groups, if both parents have O${}^{+}$ve blood groups then the child will have either O${}^{+}$ve or O${}^{-}$ve blood group.

Therefore, the correct answer is option C.