Final answer:
The best completion for the sentence 'Cuando tengo un examen, estoy_' would be 'a. nervioso.'
Step-by-step explanation:
For question 6, 'Cuando tengo un examen, estoy_,' the best completion would be 'a. nervioso' which means 'nervous' in English. When a student has an exam, they may feel nervous or anxious about it. The word 'nervioso' reflects this feeling and is the most appropriate choice to complete the sentence.
Learn more about Feelings in Spanish