Final answer:
Silver was the resource that provided the majority of the wealth extracted from the Spanish colonies in the Americas. Spain discovered rich veins of silver ore in South America, particularly in Potosí. Hence, the correct answer is option (B).
Step-by-step explanation:
The resource that provided the majority of the wealth extracted from the Spanish colonies in the Americas was B) Silver. Spain discovered rich veins of silver ore in the mountain called Potosí in South America, which became a boom town in the sixteenth century. The Spanish empire heavily relied on the silver trade to fund its economic activities.
Further evidence of the economic importance of silver can be seen in the fact that European colonies in the Americas were required to send resources like silver and gold back to Europe, and trade only with their respective 'mother' countries.