Which pronoun is appropriate for this statement: "Neither the teacher nor the students forgot (his or her, their) materials"?

In the statement "Neither the teacher nor the students forgot (his or her, their) materials," the pronoun needs to match the subject's number and gender while also respecting the collective nature of the subjects. The phrase "neither...nor" suggests that the subject is singular and refers to either of the options mentioned, which means the pronoun should ideally be singular and gender-neutral.

The choice "his or her" is correct because it appropriately reflects the singular nature of "neither" and includes both gender options, thus acknowledging the possibility that the teacher could be male or female. This pronoun also aligns grammatically, as it denotes possession corresponding to the teacher, the singular subject in the construction.

In contrast, "their" would typically be used for plural subjects, and while modern usage sometimes accepts "their" as a singular, it may introduce ambiguity, especially in more formal contexts. "Its" is unsuitable because it is used for objects or non-human entities, which does not apply here. The choice "her" is inappropriate as it is specifically feminine and ignores the potential male gender of the teacher. Thus, "his or her" remains the most appropriate and grammatically correct choice.