The correct answer is 'carriers'. Females have two X chromosomes, meaning that if one X chromosome has a trait, the female will not exhibit the trait because she still has one unaffected X chromosome. Therefore, the female will carry the sex-linked trait because she has one affected chromosome, so she can pass on the trait to her offspring. On the other hand, males have an X and a Y chromosome, meaning that if, for example, their X chromosome has a trait, they will exhibit that trait because their only X chromosome has the trait.
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