We don't usually use the word "opposite" for sentences, and instead talk of them as the negative or the positive form. The word "opposite" is usually reserved just for words, as sentences don't truly have opposites.
Anyways, to your examples for the opposite of" I have the report':
A)I do not have the report.=this is correct as the negative of "I have".
B)I have not the report.=this is NOT usually acceptable, and should be " I haven't got the report."
C)I have no report.=this is correct but is not the negative of " I have the report". It would be the negative of "I have a/one report".