Answer:
C. An event that a reader probably wouldn't have been able to predict.
Step-by-step explanation:
A "twist" can mean something unexpected/unpredictable, it is a change of events in either writing, music, dance, and many more different topics/subjects! The definition of twist in writing though represents an unexpected turn of events that can be unpredictable to the reader! So C. makes the most sense out of these option choices! :)