An effective way to improve your ability to communicate is to _______________________________________.
a. be aware of when you are the receiver and when you are the sender
b. realize that most communication is verbal
c. talk when you are decoding a message
d. interrupt the sender when necessary

Answer :

An effective way to improve your ability to communicate is to A) be aware of when you are the receiver and when you are the sender.
It is very important to distinguish between these two things so as to achieve a good communication with somebody. 
ModNov
a.  be aware of when you are the receiver and when you are the sender.