A. Dogs can not recognize the connection between color and food.
B. Dogs can not understand signals for food.
C. Dogs can not give responses to the color of food.
D. Dogs can not tell the differences in the meaning of colors.

A. To discuss the outline of his assignment with the professor.
B. To tell the professor that his assignment was lost.
C. The professor asks the student to go to his office.
D. Most students have submitted their assignments.