What Is the Basic Process for Calculating the Event Late

What is the basic process for calculating the event late time for an event in the middle of a network diagram?

A) Add the duration of the preceding activity (to the left) to its early time
B) Subtract the duration of the preceding activity (to the left) to its early time
C) Add the duration of the following activity (to the right) to its early time
D) Subtract the duration of the following activity (to the right) to its early time