The correct answer is B) A teacher knows an effective way to teach students about negative numbers.
The statement that is the best example of a teacher's pedagogical content knowledge is "a teacher knows an effective way to teach students about negative numbers."
The teacher's pedagogical content knowledge means that the school teacher has many forms to teach or instruct the students about a particular topic or subject. This diversity of forms to explain something is the product of the pedagogical experience the teacher has, which allows him to make it easy for the students to understand the lesson, using different approaches, techniques, example, activities, or group dynamics that facilitates knowledge.