Anastasia Wants to Run and Finish a Marathon

Multiple Choice

Anastasia wants to run and finish a marathon. Every day her trainer measures the distance she is able to run, and even though she is far short of the 26-mile distance of a marathon, Anastasia is praised for her daily runs. Her trainer feels that if he starts with the basic running skill and rewards her smaller efforts, Anastasia will eventually run a successful marathon. Her trainer is addressing her running behaviour by using the
Principles of _.

A) shaping
B) extinction
C) approximation
D) delay of gratification