According to the Juniper documentation1, an interface map is a configuration template that maps interfaces between logical devices and physical hardware devices (represented with device profiles) while adhering to vendor specifications. An interface map specifies a connection between the interfaces of two devices, such as a leaf and a spine, a leaf and a server, or a leaf and an external gateway. An interface map can also specify port transformations, such as breaking out a 40 GbE port into four 10 GbE ports, or disabling unused ports. An interface map can be used to achieve the intended network configuration rendering and to enable features such as LAG, ESI-LAG, or MLAG. Therefore, the correct answer is B. An interface map specifies a connection between the interfaces of two devices. Reference: Interface Maps (Datacenter Design)