Under which market structure does the action of one firm have a spillover effect on the decisions of other firms?
-oligopoly
-perfect competition
-monopoly
-monopolistic competition

I believe the answer is: Monopoly

In monopoly, the power to determine the price of a certain type of product fall to the hands of a single company. Which means, every single actions that made by this company would force other firms to conform since they do not possess enough resources to challenge this controlling company.

The part, "Canceled plans disappoint like a milk spill," is a simile.

Explanation:

Similes compare two objects/things using "like" or "as."