Which One of the Following Teaching Practices Is Definitely an Example

Which one of the following teaching practices is definitely an example of evidence-based practice?

A) A kindergarten teacher asks students to bring something from home that begins with the letter B.
B) A fourth-grade teacher uses a reading program that research has shown to be effective for fourth graders.
C) A seventh-grade science teacher asks students to conduct experiments in which they must determine which one of several variables makes a pendulum swing fast or more slowly.
D) A high school art teacher encourages students to choose a medium (e.g.,clay,watercolor paints) that they can best use to express themselves.