An explosion breaks a rock into three parts in a horizontal plane. Two of them go off at right angles to each other. The first part of mass 1 kg moves with a speed of 12 m/s and the second part of mass 2 Kg moves with 8 m/s speed. If the third part files off with 4 m/s speed, then its mass is

1.An explosion breaks a rock into three parts in a horizontal plane. Two of them go off at right angles to each other. The first part of mass 1 kg moves with a speed of 12 m/s and the second part of mass 2 Kg moves with 8 m/s speed. If the third part files off with 4 m/s speed, then its mass is

A) 17 Kg
B) 3 kg
C) 15 kg
D) 5 kg