Choose the correct word/phrase to complete the sentence. She wants to visit her mother. She is taking a __________ tomorrow.

Day off is the correct word.
Holiday - is an incorrect answer since the meaning of holiday is "a duration of rest from work or school or it is a day of rest when people do not go to work, school, etc, oftenfor religious or national events," and holiday does not fit in the sentence.
Day off is the correct answer,since the meaning of "day off" is "a day away from work, school, or a comparable duty; a free day or the decision not to work on a certain day." For example, he took the day off to go fishing, and I was tempted to take the day off, and this is the best fit in the sentence given in the question 'She wants to visit her mother. She is taking a day off tomorrow.
French leave - is an incorrect answer because the meaning of French leave is "absence from job or duty without authorization or as an informal, hurried, or secret departure."
Vacation - is an incorrect answer because the meaning of vacation is any of the periods of time when universities or courts of law are closed.