When did Congress first pass legislation to purchase and arm naval vessels?

The correct choice is grounded in the early history of the United States Navy. On 13 October 1775, the Second Continental Congress, recognizing the need for naval power to support the revolutionary effort against British rule, passed legislation to construct a fleet of vessels. This decision marked a pivotal moment in establishing a naval force for the nascent nation, emphasizing the importance of sea power in military strategy.

In this context, the other options reflect significant dates in the American Revolutionary War and the establishment of the nation, but they do not pertain specifically to the legislative action regarding naval vessels. For instance, October 1, 1776, and July 4, 1776, are notable for their relation to developments in the Revolutionary spirit and the Declaration of Independence, respectively, while May 27, 1779, does not correspond to the founding actions taken to create a naval fleet. Thus, the legislation passed on October 13, 1775, stands out as the foundational moment for the United States Navy's creation and the impetus for further naval operations.