Which of These Statements Describes What Happens When Temporal Summation

Which of these statements describes what happens when temporal summation takes place

A) Two EPSPs from the same presynaptic input occur so closely together in time that they add together, or sum.
B) An EPSP and an IPSP occur simultaneously and cancel each other out.
C) Two EPSPs that occur simultaneously from different presynaptic inputs add together, or sum.
D) Action potentials occurring in two presynaptic inputs simultaneously converge upon the postsynaptic cell, initiating two different action potentials in the postsynaptic cell.