The correct answer is (C) Heating a wheat kernel destroys its gluten, a protein that must be present in order for yeast to leaven bread dough.
Step-by-step explanation:
Two events are causally related if one of the events causes the other, which means one event originates the other. This relationship is suggested between the use of yeast and the introduction of a new variety of wheat in Ancient Egypt, which is explained in "That discovery roughly coincided with the introduction of a wheat variety". Moreover, this is better supported by the evidence "Heating a wheat kernel destroys its gluten..." because the use of the new variety of wheat caused gluten was not destroyed in the process and this was the origin of leavened bread and the use of yeast.