Although environmental factors play a role in the best parenting style for each family, according to research in the us, the one that is most effective is the style of parenting.
a.

neglectful
b.

authoritarian
c.

permissive
d.

authoritative

Authoritative parenting is the most effective style of parenting. It is a balance of authoritarian and permissive styles of parenting. 

Authoritarian parenting is bossing your kids around, and not giving much leeway or freedom.

Authoritarian is characterized by giving little to no rewards and the children giving back.

Permissive parenting is giving your kids too much freedom, allowing them to make as many mistakes as possible, and allowing them to "run the house".

Permissive is characterized by giving too many rewards while allowing the children to not give back.

Authoritative is in the middle, where parents give rewards equally with the children giving back.

So D would be correct.