Which group constitutes the largest portion of voters in terms of representation?

The group that constitutes the largest portion of voters in terms of representation is all residents. This category encompasses a broad range of individuals living within a certain jurisdiction, including citizens and non-citizens, those who are eligible to vote, and those who may not be registered. In discussions about representation, it's important to recognize that while not all residents have the right to vote (such as non-citizens), they still represent a significant portion of the population within that area.

The concept of representation looks beyond just those who participate in the voting process. It considers the voices and needs of all individuals living in the community. Hence, when we speak about representation in a political context, acknowledging all residents aligns with the inclusive nature of democratic societies, which strive to account for and advocate for the varied interests of their entire populace, not just those who are registered or eligible to vote.

In contrast, the other options focus on specific subsets of the population, such as registered voters or eligible adult citizens, which do not account for the entire community and therefore represent a smaller portion in the broader context of representation.