Option A i.e Explorers such as Christopher Columbus sought to trade for spices from India is the correct answer.
The age of discovery and exploration began in late 15th century. Trade was the most important and common reason which led the explorers to discover new lands and new routes. Indian spices (nowadays South Asia) and African gold's thirst inspired the explorers. It lead to more and more discovery of new lands.
So we see Christopher Columbus sought to trade for spices from India and ended up in discovering America.