Refer to the Figure Shown

Refer to the figure shown.
Which statement is supported by the data in the figure?

A) In freely diving seals, diving heart rate varies with dive duration in a graded manner.
B) In freely diving seals, the degree of bradycardia is proportional to dive duration.
C) In forcibly submerged seals, the degree of bradycardia is proportional to dive duration.
D) In forcibly submerged seals, the degree of bradycardia is inversely proportional to dive duration.