The defendants, employees of the Municipal Corporation opened a main hole in the street and in the evening left the mainhole open and covered it by a canvas shelter, unattended and surrounded by warning lamps. The plaintiff, an eight year old boy, took one of the lamps into the shelter and was playing with it there,when he stumbled over it and it fell into the mainhole. A violent explosion followed and the plaintiff sustained bum injuries. The defendants are:

A. Not liable because injury to the plaintiff is not foreseeable

B. Liable because they should have completed the work before they left

C. Not liable because they acted reasonably

D. Liable because injury resulted from a known source of danger even though through an unforeseeable sequence of events

Answer: Option D