Final answer:
The correct Ud. command is 'Digamelo'.
Step-by-step explanation:
The correct Ud. command is option C. Digamelo. The subject pronoun 'Ud.' is the abbreviation for 'usted', which is the formal singular 'you' in Spanish. To form the Ud. command, you need to use the third person singular form of the present subjunctive for most verbs. In this case, 'digamelo' is the correct form of the verb 'decir' (to say/tell) in the present subjunctive, meaning 'tell me' in English.
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