Final answer:
Generation Y, or Millennials, is the demographic group that is most likely to be optimistic and career-focused, as they are early in their careers and generally have more progressive social attitudes.
Step-by-step explanation:
The demographic group most likely to be optimistic and career-focused among the options provided is Generation Y, also known as Millennials (born between 1981 and 1996). Millennials are characterized by a greater acceptance of cultural and generational shifts and show more liberal stances on various social issues. They began to enter the workforce around the turn of the century and are in the early stages of their careers. This generation is managing to carve out career paths despite the changing economic landscapes and maintains a more optimistic outlook on their ability to impact the future.