A cube with sides measuring 7.69 cm is made of a metal alloy. After drilling a cylindrical hole with a diameter of 4.19 cm all the way through and perpendicular to one face, the mass of the cube is found to be 0.21 kg. What is the density of this metal? Use π = 3.14. Express your answers in whole numbers (not in scientific notation).

a) 5400 kg/m³
b) 7100 kg/m³
c) 3900 kg/m³
d) 6200 kg/m³