Final answer:
The correct expression to fill in the blank is 'tengo sed' which means 'I am thirsty' in Spanish.
Step-by-step explanation:
The correct expression to fill in the blank is C. tengo sed.
This sentence translates to 'After running, I am thirsty, so I drink a lot of water.'
The phrase 'tengo sed' means 'I am thirsty' in Spanish. It is important to use the correct verb form 'tengo' (I have) instead of 'estoy' (I am) to express thirst.
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