Three cubes of metal whose edges are 3 cm, 4 cm and 5 cm are melted to form a bigger cube. If there is no loss of metal in this process, then the diagonal of the bigger cube, in centimeters, is

• A. \(3\sqrt 3\)
• B. \(4 \sqrt 3 \)
• C. \(8 \sqrt 3 \)
• D. \(6 \sqrt 3 \)