The right answer would be the third choice - forty five. We use hyphens for words in phrases like ex-boyfriend and non-alignment. In the case of numbers, all two-word numbers from twenty-one to ninety-nine must be hyphenated.
<em>Um... You have to include the text that goes along with this story so that we can answer the question correctly. I don't want to make you mad about this because I know that there are people who would get mad about this sort of thing but I just wanted to let you know that without the text we won't be able to answer your question the correct way, meaning that you would likely get it wrong.</em>
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<em>Thanks for reading this and have a Merry Christmas,</em>
<em>Miri</em>