Final answer:
The increase in piracy against Spanish treasure ships best supports the argument on how competition influenced exploration, as it exemplifies European nations' rivalry and pursuit of wealth in the Americas.
Step-by-step explanation:
The economic and military competition between European powers significantly influenced New World exploration as nations sought to amass wealth and power by exploiting overseas territories. Option C, which refers to the increase in piracy as European powers attempted to capture Spanish treasure ships, best supports the general argument within the provided excerpt. This is because it directly relates to the inter-European rivalry and the efforts to seize wealth acquired from the Americas, thereby bolstering their national wealth and military capabilities.