How did the crusades bring about the end of the dark ages in europe? what was the "spark in the dark" that ended the "darkness" of the middle ages

a. science-europeans were able to study the stars (astronomy) the way that the muslims had already been studying astronomy

b. engineering-europeans were able to study new designs of building that had already been introduced in the muslim "world"

c. education-europeans were able to study new forms of mathematics that were already being studied in the muslim "world"

d. wealth of knowledge-so much information was brought back from the muslim "world"; information pertaining to medical knowledge, new forms of mathematics and education, "aristotle was brought back," and "everything was brought back"; so many new ideas were brought back to europe from the muslim "world"