Answer:
The correct answer is - C. prolonged elevation of presynaptic calcium levels following synaptic activity.
Step-by-step explanation:
Synaptic facilitation is a process of short-term plasticity that transiently increases synaptic transmission for less than a second, which is considered an essential part of playing a critical role in information transfer and neural processing.
It is evident that such an increase in the synaptic transmission is occur due to prolonged elevation of presynaptic calcium levels following synaptic activity.