Answer:
B. He is stronger and more mature.
Step-by-step explanation:
As Heathcliff enters the parlor, Nelly takes note of that he looks imposing, mature, and dignified, in contrast to his youthful roughness. However despite everything he holds a sort of "ferocity" in his eyes.
Heathcliff has gotten away from the lower class "roughness" forced on him by Hindley however holds his wild nature.