Final answer:
Under-18 individuals can influence elections through participation in youth advocacy, volunteering for campaigns, and motivating eligible voters to vote.
Step-by-step explanation:
A person under the age of 18 can legally influence the outcome of an election in several ways, even though they cannot vote. They can participate in youth advocacy groups, volunteer for political campaigns, and encourage eligible family members and friends to exercise their voting rights. By engaging in these activities, young people can have a substantive impact on political outcomes by raising awareness, providing assistance to candidates or parties they support, and increasing voter turnout among those who can vote. The way in which young people can contribute suggests that all the options provided - a, b, and c - are correct. It is important for young people to realize that political engagement goes beyond just casting a vote and there are many avenues available to them to influence elections and policy.