What must exist before creating a Slack CLI project if you don't already have a...

Slack's current quickstart recommends using a developer sandbox when a developer does not already have a suitable Slack workspace for application development. A developer sandbox provides an isolated environment where an app can be installed, tested, and iterated without disrupting a production workspace. Slack CLI includes sandbox-related tooling, and the quickstart treats the sandbox as the preferred development environment for users who lack an existing workspace. A paid Slack plan, Enterprise Grid organization, or verified domain is not a prerequisite simply to begin a Slack CLI project. Strictly speaking, Slack documentation frames the sandbox as the recommended development workspace rather than a universal technical requirement in every circumstance; however, among the supplied choices, B is unequivocally the intended and correct answer.