Which of the following statements represents a productivity way to maintain a horizontal relationships

The correct answer is this one: "C. Helping a coworker with a task when you're done with your task."

In horizontal relationship, it is necessary to help a coworker with a task especially when you are done with yours in order to be more productive. 

Here are the choices.
A. Socializing frequently during the day
B. Sharing responsibility to make sure your work gets done
C. Helping a coworker with a task when you're done with your task
D. Telling others to do your work because you can't get the work done