I did the following (barring corner cases as mentioned previously) and it seems to strip comments just fine: 
cat t.xml | perl -e '$/ = ""; $_ = <>; s/<!--.*?-->//gs; print;'

[download]
which gave the output: 
<Node_A>
    
    <Node_B>
        
        <Node_C>
        </Node_C>
        
        
    </Node_B>
</Node_A>

[download]

In reply to Re^2: Removing XML comments with regex by tuxz0r
in thread Removing XML comments with regex by gasho

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