7-97J2 B
 A ship at anchor has been communicating with a shore station approximately 350 miles distant on a frequency in the 4 MHz band through early afternoon. Toward the late afternoon and evening, what effect should be noticed?
A. Communications should be maintained with slight improvement in the signal received from the shore station.
B. Communications should gradually improve and peak at night and early morning.
C. Communications should slowly deteriorate but may be continued throughout the night.
D. Communications should gradually deteriorate and become impossible on this frequency by night.
