I would say b because the games that are in the halls were nominated to be hall of fame games
Polonius is using his daughter to spy her conversation with Hamlet. He teaches how to act naturally, how to walk and pretend that she is reading.
In that last phrase, he is saying that we humans often act in deceitful ways, for which we are to blame.
He admits that he is making a mistake, in teaching that kind of behaviour to his own daughter.
A IS IT I THINK Sorry cap lock was on
B, It's two independent clauses tied together using a conjunction.