Answer:
B. frozen
Step-by-step explanation:
An open first syllable is one that has a vowel at its end and that vowel causes a long vowel sound at its end. Long vowel sounds are those sounds whose pronunciation is the same as those of the letters.
Among the words listed, fro-zen has a long vowel sound in the form of the o at the end of the first syllable. Thus it can be classified as having an open first syllable.
