4.23×107 m/sec4.23\times 10^7\mathrm{~m}/\mathrm{\sec }4.23×107 m/sec
1.41×107 m/sec1.41\times 10^7\mathrm{~m}/\mathrm{\sec }1.41×107 m/sec
9.0×107 m/sec9.0\times 10^7\mathrm{~m}/\mathrm{\sec }9.0×107 m/sec
None of these\text{None of these}None of these