A Boy Plays Solitary Seesaw by Placing a Long Plank

Multiple Choice

A boy plays solitary seesaw by placing a long plank over a small rock and sitting at one end of the plank.When the seesaw is balanced,the boy's mass is most likely

A) greater than the mass of the seesaw.
B) less than the mass of the seesaw.
C) equal or very nearly equal to the mass of the seesaw.
D) Not enough information is given.