modified the options a little bit.

Although early soap operas were first aired on evening radio in the 1920's, they had moved to the daytime hours of the 1930's when the evening schedule became crowded with comedians and variety shows.


(B) were first aired on evening radio in the 1920's, they were moved to the daytime hours in the 1930's
(C) were aired first on evening radio in the 1920's, they were moved to the daytime hours in the 1930's
[spoiler]
Is there is some difference in the meaning of the above 2 options.
Looks like, but couldn't express it.[/spoiler]