Answer:
a. they integrate activity within a single brain structure.
Explanation:
This can be local interneurons and relay interneuron based on function and structure.
Based on function the interneuron synapse with the sensory and motor neurons,This structural characteristic is related to their functions. Thus as sensory neurons synapse with the Interneurones, the recieved message from sensory neuron of the spinal cord first branched off to the brain for processing and analysis, and output (response) from the brain returns to the interneuron , which synapse this with the motor neurons, for transmission to the effectors.
This type of information integration and processing is especially important when processing information from high brain centers, and complex tasks,and it involved the relay interneuron. This explains the integration function within the brain structure.
However if the information is simple the local interneuron mediated this/ a sensory information is not sent to the brain. Rather the information is transmitted from the sensory to the motor , coordinated by the spinal cord and response is transmitted to the effectors.