27 You ..... be hungry again, Paul! You just had dinner.

Analysis:

The sentence expresses disbelief or impossibility that Paul is hungry again so soon after dinner. The modal verb 'can't' is used to express this impossibility or strong disbelief.

Breakdown:

• A can't: Correct. 'Can't' expresses impossibility or strong disbelief.
• B mustn't: Incorrect. 'Mustn't' expresses prohibition.
• C may not: Incorrect. 'May not' expresses possibility of not doing something, or a polite negative, not strong disbelief.

Translated Question:

27 Ты ..... снова голоден, Пол! Ты только что поужинал.