[单选题]
Which of the graphs b :(:ci3x 9qzx.kq4l9enkhp pd elow bei-z nc8 e,; bewj+xe::wze9tsst describes the change in average kinetic energy of the molecules of a beaker of water as it is heated at a ct ;ejee:nwz :,x98we c+b zi-sonstant rate until it completely boils away?