A diagram showing axon terminal and synapse is given. Identify correctly at least two of A - D <br>

Question

https://clay6.com/mpaimg/499_a.jpg

( A ) A - Receptor; C - Synaptic vesicles
( B ) C - Neurotransmitter; D - $Ca^{++}$
( C ) A - Neurotransmitter; B - Synaptic cleft
( D ) B - Synaptic connection; D - $K^+$