In a Venn diagram with sets $X$, $Y$, and $Z$, if you are given that $|X| = 150$, $|Y| = 120$, $|Z| = 90$, $|X \cap Y| = 60$, $|Y \cap Z| = 40$, $|X \cap Z| = 35$, and $|X \cap Y \cap Z| = 15$, which region has the most elements: $X$ only, $Y$ only, $Z$ only, or the intersection of all three?