There are five criteria for effective marketing segmentation: $1)$ identifiable, $2)$ measurable, $3)$ substantial, $4)$ accessible, and $5)$ responsive. Which of the following segmentation variables best meets the "accessible" criterion?

Members of the segment typically vote democrat.

All members of the segment are active on popular social media and the Company primarily advertises on social media.

The segment represents approximately $200$ million people.

The segment represents $$100$ million in potential revenue and requires a roughly $$10$ million investment into the marketing mix.