Which of the following is NOT a neuter gender? 

There are four distinct noun genders in English: masculine, feminine, common, and neuter. Words denoting a male figure or male member of a species are referred to as Masculine Nouns. Female members of a species or female figures are denoted by Feminine Nouns. Common nouns do not specify the gender when referring to members of a species. Neutral nouns are used to describe things without a gender. Typically, a neuter gender is an inanimate object, plants and animals, child, infant etc. The teacher is the "common gender," so that is the correct answer.