Question

the primary means of mass communication changed from what to what in the mid - twentieth century?
from television to the internet
from telegraph to radio
from telephone to newspaper
from radio to television

Explanation:

In the mid - twentieth century, radio was a dominant mass - communication medium before television became more prevalent. The internet became a major mass - communication tool later, telegraph and telephone are not primary mass - communication in the context of the question, and the shift from telephone to newspaper is not correct for this time period.

Answer:

From radio to television