What is meant by same layer interaction

• That a packet is forwarded to a different host that resides in the same layer of the Cisco three layer hierarchical model.
• That an interaction occurs within a single layer of a networking model and that no other layers or devices take any part in the interaction.
• An interaction that progresses up or down only one level of a networking model.
• That two computers use a protocol defined at the same layer of a networking model to communicate with each other.