You're an Org Primary Owner on your company's Slack Enterprise Grid.

Slack recommends using an org-wide channel for announcements:

"An org-wide channel ensures that important updates reach every member across all workspaces. Bookmarking learning materials in the channel also provides members with easy access to ongoing resources and updates."

Options B and C place too much burden on members to seek out information. D is reactive (waiting for questions) rather than proactive enablement.

(Reference: Slack Administration Study Guide - Managing Change and Member Enablement)

===========

—