Final answer:
Triticale is a cereal grain produced by crossing rye and wheat, where wheat is the correct answer. Therefore, the correct answer to the student's question is: a) Wheat.
Step-by-step explanation:
Triticale is a kind of cereal grain that is produced by crossing rye and wheat. This hybridization process involves combining the qualities of both parent species to create a new plant with desired traits, such as improved hardiness or yield. Wheat is a staple cereal known for its various species, including einkhorn wheat, emmer wheat, and bread wheat, with the latter being a result of a similar hybridization process involving emmer wheat and a species of Aegilops. Therefore, the correct answer to the student's question is: a) Wheat.