All 7 "Cs" are important but Which is the most important "C" in Business Communication?

In my opinion, all7 C's carry equal importance in business communication.

Courteous........................................................................

All are so important but as I belong to Finance department my first choice is Complete..

Business communication is imperfect without any of the "C" so every "C" has its own and equal importance. 

Being a marketer, my first choice would be COMPLETE

Completeness is most important. if your message is missing all is useless

All are important with Concrete on top of my list.

Thank u for the invitation. I think clarity of instruction is most important. This is more so if we are communication in English and for none of us it is the native language. We should talk slowly and clearly in a neutral accent. Should rephrase the statement to know that what we understand is what the other party means.  This is of utmost importance when the client is a multinational and wants the Indian ITES BPO industry to serve their global customers. 

Next comes Courtney. However stresses u may be u must be professional in your communication. Rudeness is out of question. frustration should not be showing in the voice even after a long negotiation even if u are at the receiving end. Do not take anything personally. 

Clear....;;;;;;;;;;;;;;;;;;;;;;;;;;;

All7 'C have it's own importance but depends how someone can implement these in Business Communication. We can not skip any need among these7.

All of them are equally important. More importantly, I believe that one C is missing from this list. Any guesses? 8th C for "confident". If you want your audience to have confidence in what you tell, you first need to deliver it confidently.