Which of the following frequencies are used on dual-frequency NAVTEX receiver?
选项：
A: 486 KHz and 462 KHz
B: 4209.5 KHz and 518 KHz
C: 518 KHz and 490 KHz
D: 490 KHz and 4209.5 KHz
发布时间：2024-04-01 11:51:58
