24.A 0.5-kg bullet is flying toward east (→) with a speed of 200 km/hr and suddenly blows up itself into four pieces. The mass of these four and the flying speeds and directions of three pieces are shown in Fig. 5. Please find the speed and direction of the last one. (A) south-west, 37.6°, 233.5 km/hr (B) south-west, 60°, 250 km/hr (C) north-west, 25.6°, 325 km/hr (D) north-west, 15°, 178.6 km/hr