It was for Natural resources, renaissance, overpopulation, and for religious reasons. Hope this helps.
The correct answer is: d. Motet.
The motet is a polyphonic composition born in the 13th century, made for singing at mass as a Latin religious choral composition, with biblical texts commonly. Until the 17th century it remained as one of the most important musical forms of polyphonic music. It was also characterized for its various melodies.
In the 15th century and the 16th century it expanded as a polyphonic vocal piece without instrument backing, a capella, with dynamically contrasting vocal lines with a imitative and dramatic character. It was one of the prominent polyphonic forms of Renaissance music.
I think it would be the failure to pass treaties. European nations are often in conflict over land territories and vast riches of the country. Another reason why the European countries always care in conflict, it would be religion. Many of them are firm believers Christianity. I think this was the reason why there was Crusades occur.
It was very rough for them. They had to constantly be working usually without a break. They had to put a lot of effort to get the job they needed to do done.
Hope that helped!!