Why Do State and National Governments Lack Accountability Under the System

Why do state and national governments lack accountability under the system of federalism?

A) Shared responsibility can sometimes cause inaction over who should implement a policy.
B) Lawmakers often get into arguments over who is responsible due to states' reserved powers.
C) State governments tend to preempt national laws, which cause confusion among citizens.
D) Both the federal and state governments are subject to extreme gridlock when making laws.