Final answer:
Behrman accompanies Sue because he cares to protect the two young artists, despite his rough exterior.
Step-by-step explanation:
The reason why Behrman likely accompanies Sue up to her studio is c. because despite his biting nature, he does care to protect the two artists. Throughout the story, Behrman is portrayed as a cantankerous old man who despite his gruff exterior, has a hidden depth of character and concern for his friends. This is a pattern often seen in literature, where a seemingly rough individual beneath the surface displays a heart of gold, especially concerning those they are close to. Furthermore, his role in the story reaches a significant gesture that only solidifies his protective stance towards the young women.