What is the meaning of this simile?

Question

“. . . a single dim ray, like the thread of the spider, shot out from the crevice. . . “
A. Light from the lantern lit up all the cobwebs in the room.
B. The light from the lantern was so slight that it was like a single thread spun by a spider.
C. Opening the lantern let spiders swarm the room.
D. The patterns in the light from the lantern resembled spider webs.

Answer 1

B. The light from the lantern was so slight that it was like a single thread spun by a spider.