Refer to the Figure Shown

Refer to the figure shown.
Which statement is the most accurate conclusion that can be drawn from the data in the figure?

A) The hamster's hypothalamus was destroyed, and therefore it could not control the animal's circadian rhythm.
B) The thalamus is significantly involved in the circadian rhythm of the golden hamster.
C) The suprachiasmatic nuclei are significantly involved in the circadian rhythm of the golden hamster.
D) The suprachiasmatic nuclei are likely not involved in the circadian rhythm of the golden hamster.