(C) vs ©

[Shriramana Sharma <samjnaa@gmail.com>]

Hello.

I have heard that in copyright declarations like:

-----------
Copyright (C) 2007, Company X, Country Y. All rights reserved.
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it is incorrect to use (C) in place of the symbol © which is the strict 
copyright symbol. Is this so? If yes, why?

Further, whether (C) or ©, isn't it superfluous to use it after the word 
"copyright" which itself means the same thing?

Thanks for your advice,

Shriramana Sharma.