W hich of the following is characteristic of small synaptic vesicles?

A) They contain neurotransmitters made only in the soma.
B) Their contents show as a dense core in electron micrographs.
C) They are about 100-300 nm in diameter.
D) They fuse with the presynaptic membrane less than 1 ms after an action potential.
E) They are generally more than 50 nm away from a Ca²⁺ channel.