What is the correct spelling of the missing word? "That is your fifth ______ this month," the teacher remarked sternly.

The correct spelling of the missing word in the sentence is "absence." This term refers to the state of being away or not present, which fits perfectly in the context of the sentence, where the teacher is remarking on a student's repeated non-attendance. "Absence" is the standard and accepted form in English for describing this condition.

The other options do not convey the intended meaning in this context. For instance, "abscence" and "absense" are misspellings and are not recognized as valid words. "Abscess," on the other hand, refers to a medical condition characterized by a collection of pus that occurs in response to infection, which does not relate to the context of attendance or being present. Thus, "absence" is clearly the appropriate choice for this sentence.