How many potential collision domains are present in the network in the following figure?

In the figure, there are three collision domains present. Keep in mind that a collision domain is a network segment in which a collision can occur and the colliding frame is created. A switch will create collision segmentation as seen in the figure. There is one giant broadcast domain, but this is not going to affect collisions. You could argue that only two collision domains exist on both of the hubs. However, you would assume that the router and switch were configured full-duplex, avoiding collisions. So, it should always be assumed that half-duplex communications is in operation, because it is possible. Seven collision domains is a wrong answer.