D. Candidates need to pay attention to how their personal appearance might after public opinion
Explanation:
The first four presidential debates on television happened in 1960 during the presidential election between Democratic nominee John F. Kennedy and Republican Richard Nixon, this debates provided voters the opportunity to compare both nominees and while Richard Nixon was well prepared and had great answers but did took care of his image, John F. Kennedy proved the importance of public image, he showed a clean aspect and good looks and gained confidence on American voters.
