In this case, "each student" is the appropriate choice to maintain a consistent singular reference, as "everybody" refers to all individuals in the singular form. "Each student" indicates the singular responsibility of each individual, which follows the conventions of Standard English.

The correct choice of pronoun-antecedent agreement is "one of them" because it refers to either Lena or Olivia in a singular manner while maintaining consistency in reference and adhering to the conventions of Standard English.

Them is the correct choice of pronoun-antecedent agreement to maintain consistency in plural reference, as "the musicians" refers to all musicians involved. "Them" denotes the group of musicians, following the conventions of Standard English.

In this case, "each member" is the appropriate choice to maintain a consistent singular reference, as "team members" refers to all individuals. "Each member" indicates the singular responsibility of each member, which follows the conventions of Standard English.

Here, the correct choice of pronoun-antecedent agreement is "his or her" because "each musician" is a singular reference. The pronoun "his or her" indicates that the musicians can be either male or female and maintains a consistent singular reference, which follows the conventions of Standard English.