Find the area of an equilateral triangle whose side is 4 cm long.

• A. \[4\sqrt{3}\,c{{m}^{2}}\]   
• B. \[2\sqrt{3}\,c{{m}^{2}}\]
• C.  4    
• D. \[8\sqrt{3}\,c{{m}^{2}}\]
• E. None of these