Which option is correct for conduction of nerve impulse along chemical synapse?

(i) At synapse the membranes of the pre and post-synaptic neurons are separated by a fluid-filled space called synaptic cleft.

(ii) Chemicals called neurotransmitters are involved in the transmission of impulses at these synapses.

(iii) The axon terminals contain vesicles filled with these neurotransmitters.

(iv) When an impulse arrives at the axon terminal, synaptic vesicles release their neurotransmitters in the synaptic cleft.

(v) The released neurotransmitters bind to their specific receptors, present on the pre-synaptic membrane.

(vi) Opens ion channels allowing the entry of ions which can generate a new potential in the post-synaptic neuron.

(vii) The new potential developed is only excitatory.