What Were the Most Compelling Forces Undermining Feudalism in the Fifteenth

What were the most compelling forces undermining feudalism in the fifteenth and sixteenth centuries?

A) the expansion of exploration and trade, and subsequent increasing demand for goods and services
B) the growth of universities and theological colleges and the subsequent decrease in religious conviction
C) the increased demand for military personnel to assist with foreign campaigns and subsequent lowered birth rates
D) the increase in infectious diseases and subsequent decline in population