In the 13th century, the crossbow was created. A footsoldier could use the crossbow to penetrate a knight's armor. Therefore the crossbow was the most reasonable strategy of attack if you were to deal with a knight
I believe the correct answer is D. Land in the West was often very inexpensive because not only was the voyage from Europe to the new world dangerous, but the land voyage to the West from the East was risky as well
Hope this helps
Farming of plants and animals