\[7\] similar iron balls and \[4\] similar steel balls have a total mass of\[7.4\,\,kg\]. Find the mass of each steel ball if each iron ball weighs\[560\,\,g\].

• A. \[870\,\,g\]                    
• B.                    \[3480\,\,g\]       
• C.                    \[780\,\,g\]                    
• D.                    \[3920\,\,g\]