Because they did not have the technology to resist without getting killed
The answer is object permanence.
Object permanence refers to the ability to understand that an object is still present and physically exists even if it is hidden out of sight. In this example, your niece lacks object permanence since she does not understand that you are behind the blanket even though you cover yourself with it or you are temporarily.
I believe it is B because I remember that there are Buddhist there sorry if it not correct but I think it is
This is true. Politeness and respect go hand in hand. :)