According to the article titled “enlightenment,” philosophers believed that human beings had the ability to which no other creature possessed.
a. learn
b. reason
c. understand
d. communicate

B. Reason

Explanation:  What makes human beings apart from others is reason, since, for example, animals have the ability to communicate and learn many skills of hunting, hiding, etc. According to Enlightenment philosophers, human beings have reason, as a natural ability based on natural laws. Thus, a new way of thinking about the outside world has been established, not on the basis of church rules, but through the observation of the natural world, its examination, the establishment of scientific theories and reasoning.

answer; /// i believe that its (c) universal symbols;