How many broadcast domains are present in the network in the following figure?

In the figure, only one broadcast domain exists because a PC on the left hub can send an ARP request and the PC on the right hub can hear it. If you wanted to create multiple broadcast domains, you would need to create VLANs and route them. Two, three, and seven broadcast domains could be achieved by creating additional VLANs and a router-on-a-stick configuration with the router between the VLANs.