To analyze the action and reaction forces in the context provided (though I can't see the picture), we can assess the statements based on Newton's Third Law of Motion, which states that for every action, there is an equal and opposite reaction.
Let's evaluate each option:
a. The book is pushing on the table and the table is pushing on the book.
This statement describes a correct pair of action-reaction forces. The book exerts a downward force on the table (action), and the table exerts an upward force on the book (reaction).
b. Friction is pushing up and gravity is pulling down.
This option does not explicitly reference an action-reaction pair, and while gravity does pull down, friction typically acts in the direction opposite to motion (not "pushing up").
c. The flower vase is pushing up and gravity is pulling down.
This option does not accurately reflect an action-reaction pair; it mixes the upward force against gravity but does not articulate a corresponding reaction.
d. Gravity is pulling the book downward.
While this describes a force acting on the book, it does not illustrate an action-reaction pair as required by Newton's law.
Based on this analysis, the best answer reflecting true action-reaction forces is:
a. The book is pushing on the table and the table is pushing on the book.