Final answer:
The term "un rêve" in the sentence translates as "a dream" in English. The complete statement seems to be a mix of English and French and would correctly be "ça doit être un rêve!" meaning "it must be a dream!"
Step-by-step explanation:
In the sentence you provided, "ça has to être un rêve!", the term "un rêve" translates to "a dream" in English. Therefore the correct option would be option 2: A dream. The statement overall though, appears as a mix of English and French languages and is grammatically incorrect in both. If translated correctly to French, it should be "ça doit être un rêve!" which means "it must be a dream!" in English
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