he correct answer is D) A viewer's guide from the Public Broadcasting Service
Step-by-step explanation:
A viewer's guide contains information about the programs, channels, and content of a television broadcasting service. Due to this, if you want to know the number of educational programs in public television the best source is a viewer's guide. Besides this, as the programs you are interested in are broadcasted in public television the best type of viewer's guide in one from the public broadcasting service as one for cable television programming contains non-public educational programs. Thus, the best source is "A viewer's guide from the Public Broadcasting Service".