Final answer:
The year of the Spanish Armada was 1588 (option a). The fleet, sent by King Philip of Spain, was defeated by the English navy, marking the decline of the Spanish Empire.
Step-by-step explanation:
In 1588, the year of the Spanish Armada was 1588 (option a). The Spanish Armada was a fleet of ships sent by King Philip of Spain to defeat England and Holland, and deal a blow to Protestantism. However, the fleet was defeated by the English navy led by Lord Charles Howard and Sir Frances Drake. This defeat marked the beginning of the end of the Spanish Empire.