To ensure that DSW1 becomes the root bridge for VLAN 10, the commands A and B should be used.
Command A DSW1(config)#spanning-tree vlan 10 priority 4096 sets the priority of DSW1 to a lower value making it more likely to become the root bridge as in STP (Spanning Tree Protocol), the switch with the lowest priority value becomes the root bridge. Command B DSW1(config)#spanning-tree vlan 10 priority root is a macro that automatically sets the switch's priority to ensure it becomes the root for VLAN 10.
References := Cisco