Answer:
d. All of these
Explanation:
A synaptic cleft or synaptic gap is formed during synapsis. It is a gap between membrane of a axon end bulb and a membrane of a target cell. The target cell can be a muscle cell, a neuron, a gland. The membrane of a axon is called pre-synaptic membrane and membrane of a target cell is called post-synaptic membrane and the space between two membranes is called synaptic cleft. Through the synaptic cleft impulse is transmitted with the help of neurotransmitters such as acetylcholine.
