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Answer:
F altitude
Explanation:
AB is perpendicular to triangle base XZ, so is an altitude of the triangle.
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Additional comment
B is not the midpoint of XZ, so AB is not the median and not a bisector of XZ. Likewise, AB is not the angle bisector of angle A. (The triangle would have to be isosceles for AB to be a perpendicular bisector, median, and angle bisector.)
Eliminating the choices that can't work leaves the one that does work. AB is the altitude.