Final answer:
Spain and Portugal sought new routes to Asia to avoid the high costs imposed by Ottoman and Venetian middlemen, further driven by religious purposes and the desire to establish profitable trade routes. The correct option is B.
Step-by-step explanation:
The Spanish and Portuguese were pushed to find new routes to Asia primarily due to the rising cost of Asian goods passing through Ottoman and Venetian ports. This was a result of increased taxes and fees imposed by Muslim middlemen along the overland trading routes such as the Silk Road, which made these routes expensive and slow.
In addition, European nations like Spain and Portugal were motivated by religious zeal and the desire to weaken the Muslim world while strengthening the Christian world by diversifying trade routes. Seeking to circumvent these routes led to an era of exploration, culminating in events like Columbus's 1492 voyage, sponsored by Spain, in search of an oceanic route to India (Age of Exploration).
Hence, Option B is correct.