Option (B) synapse is correct. According to the textbook context, at the end of the axon, the electrical impulse sets off the release of some chemicals. These chemicals cross the gap, or synapse, and start a similar electrical impulse in a dendrite of the next neuron. The text explicitly states that synapse is the gap between two neurons. The other options are incorrect because: dendrite is the part of a neuron where information is acquired; axon is the part through which the electrical impulse travels; and impulse is the electrical signal itself, not a structural gap.