I would say D is the correct answer.
The answer is A. It distributes power among three branches of government
It eroded it because the colonists were forced to fight the French on the American territories. They didn't want to do this because the French were good trading partners and the colonists had good relations with them, so they became unsatisfied that they were drawn into a war that was against their well being by the British.
There were lots of uncontrollable strikes in Petrograd, ones which he tried to send out his army to to save. However, his soldiers then refused to let fire on the protesters. He then weakened a huge amount and lost great chunks of his supporters. This meant he had to abdicate
