How many times had Mrs. Starch missed school in 18 years?

Mrs. Starch's attendance record demonstrates her dedication and commitment to her profession, as it reveals that she has missed school only once in 18 years. This infrequent absence indicates not only her reliability as an educator but also an exemplary sense of responsibility towards her students and duties. The significance of such a record can also reflect on her health, personal circumstances, and the values she holds regarding her role in the educational environment.

In the context of the other choices, they suggest a higher frequency of absences, which would not align with the image of a dedicated teacher that is implied in the scenario. The option indicating five or three absences suggests a more common experience among educators, while the choice of never missing school implies an unrealistic standard of attendance. Therefore, the information that she missed school only once is the most accurate reflection of her commitment and reliability as a teacher.