A.3 B.4 C.8 D.12
A.besides the polar regions B.including the North Pole and the South Pole C.above 70°N and below 70°S D.as for north and south as 70°
A.be transmitted at once though the frequency is not clear B.be transmitted as soon as the frequency is cleared coordinately C.be transmitted at its scheduled transmissions D.be transmitted at next scheduled transmissions