In which of the following sentences are the pronoun and antecedent not in agreement?

A. The teachers and the principal called all of their students to come to the assembly.
B. Running out of air, Robert swam quickly to the surface to catch his breath.
C. The children played all day long outside on their swing sets.
D. Neither Sally nor Robert called their parents.

Question

In which of the following sentences are the pronoun and antecedent not in agreement?

    A.	The teachers and the principal called all of their students to come to the assembly.
   B. Running out of air, Robert swam quickly to the surface to catch his breath.
    C.	The children played all day long outside on their swing sets.
    D.	Neither Sally nor Robert called their parents.