Final answer:
Social mobility in pre-Enlightenment Europe was difficult, but not impossible, as there were a few avenues for upward mobility.
Step-by-step explanation:
Social mobility in pre-Enlightenment Europe was difficult, but not impossible. While social status was largely determined by birth and wealth, there were a few avenues for upward mobility. Families could improve their social status through hard work, good luck, and study. It was also possible for gentry families to sink back into the working class if their sons refused to work or study. Therefore, option (c) Difficult, but not impossible, as there were a few avenues for upward mobility, is the correct answer.