Answer:
d. had longer sound bites, on average, in broadcast television newscasts.
Explanation:
According to historical records and observation, Presidential candidates in the 1960s, compared with today, "had longer sound bites, on average, in broadcast television newscasts."
Today, many news outlets are more into sensational news, thereby care more about their opinions and views of the electorates on the presidential candidates and their odds of winning the election rather than putting more of the short extract from a recorded interview or speech in their news report.