Final answer:
President Kennedy's focuses were on public service and national dedication, best represented by the idea that citizens' willingness to serve is crucial for a stronger nation.
Step-by-step explanation:
President Kennedy's central focuses to better the nation were primarily about public service and national dedication. The idea that best represents his vision and actions is C. Success depends on citizens willing to be of service. Citizens must seek opportunities to build a stronger nation. Kennedy's inaugural address emphasized this by urging Americans to contribute to their country with the famous quote, "Ask not what your country can do for you; ask what you can do for your country." His administration sought the involvement of talented individuals dedicated to public service, and he aimed to inspire the country to undertake new challenges,
such as winning the space race and fighting poverty. Kennedy's approach also involved addressing civil rights and ensuring equality, although progress in this area was cautious due to political sensitivities.