Step 1: Understanding the Concept
A synapse between two neurons is named after the parts of the two cells that come in contact.
Step 2: Check each type
Axo-dendritic: axon meets dendrite, the commonest type.
Axo-axonic: axon meets axon.
Dendro-dendritic: dendrite meets dendrite.
Dendro-somatic: dendrite meets cell body.
Step 3: Conclude
All four types are possible between two neurons.
Final Answer:
All of (A), (B), (C) and (D) are correct.
\[ \boxed{\text{(C) }\text{(A), (B), (C) and (D)}} \]