You learned about the general concept of parallax in chapter 2, and the video offers a review of the basic ideas. to check your understanding of the concept, which of the following is a valid way of demonstrating parallax for yourself?
a. look up at a star, and notice how it moves toward the western horizon during the night.
b. hold up your hand in front of your face, and alternately close your left and right eyes.
c. hold up your hand in front of your face, and move it slowly back and forth.
d. get a camera, and photograph a person who is running back and forth.