The correct answer is A. When California applied for statehood, the Southern states feared that they would lose equality in the Senate. Before the admission of California, Southern slavist states and Northern free states had the same number of Senators. But when California was admitted in 1850, it entered into the Union as a free state, so it created a power disbalance for the Southern states, giving to extra votes to the abolitionist states.
McCulloch v. Maryland (1819) is one of the first and most important Supreme Court cases on federal power. In this case, the Supreme Court held that Congress has implied powers derived from those listed in Article I, Section 8. The “Necessary and Proper” Clause gave Congress the power to establish a national bank.