Final answer:
The word vacation has a first syllable that is an open syllable (V/CV).
Step-by-step explanation:
In the word vacation, the first syllable is an open syllable (V/CV). The va is the first syllable and it has a vowel sound (a) followed by a single consonant sound (c). Therefore, the word vacation has a first syllable that is an open syllable (V/CV).