What kind of view can be layered temporarily over the current screen to collect input...

A Slack modal is a temporary focused interface displayed over the current Slack experience. Slack describes modals as alert boxes, pop-ups, or dialog boxes that capture and maintain user focus until the modal is submitted or dismissed. Applications commonly use modals for structured forms, configuration tasks, data entry, confirmation flows, and detailed information that would otherwise clutter a message or Home tab. Modal views are built using Block Kit and can contain input elements, select menus, buttons, text, and other supported components. Applications normally open them through `views.open` using a recently generated `trigger_id`. Channels and workspaces are persistent Slack organizational structures, while workflow triggers begin automations rather than rendering focused pop-up interfaces. Therefore, A is correct.