The correct answer is C. Dynamic action.

Dynamic Actions allow an app builder to control which actions appear on a Lightning record page and apply filters to control action visibility. Salesforce documentation states that Dynamic Actions can be assigned in Lightning App Builder and visibility filters can control when actions are shown.

For this requirement, the custom Sync action can be shown only when the Account custom Status field equals Ready to Sync. A custom link alone does not provide the same Lightning App Builder visibility control, a formula field cannot call the Lightning Web Component action, and an AppExchange product is unnecessary.

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