Answer: A. True
Step-by-step explanation:
An understudy is a person who works closely with a staff in a higher position (for example, a manager), learning the important aspects of the job so as to be able to fill up for the senior staff, should he leave the organization, or be absent for any other reason.
The understudy learns the secrets of the senior position. He also has a knowledge of passwords, presentation delivery, and access to important documents. This makes it easier for the organization to fill up an important role and not suffer for long in looking for a replacement after the departure of the senior staff.
Since Colin works closely with the experienced manager, he would learn all the important functions involved in credit management. So he is an Understudy who can be easily called upon to replace the manager, should he exit the organization.