The correct answer is A) from the silver mines at Almadén.
Other than heavy taxation, the Spanish monarchy obtained money from the silver mines at Almadén.
Spanish King Philip II, son of Charles V, inherited a kingdom full of debts and the crown was short of cash to repaid the debt to its debtors. Historians consider that the debt ascended to 36 million "ducats" which was the currency of the time. So the king ordered heavy taxation to its territories and exploited the silver mines in Almaden, modern-day San José, California.