study of the forces involved when motor proteins move subcellular structures in cells, Shtridelman et al. * studied the motion of objects in living cells: In this paper, they extracted the position of vesicle using video Some of the frames are shown in the figure, along with graph of the position of one of the vesicles that moved along straight line (in direction they call y): 'Force-Velocity Curves of Motor Proteins Cooperating In Vivo, Shtridelman et al,, Cell Biqchem Biqphys: 52(1): 19-29 t=0s t=2s E D { A t=6s te4s t (s) Six instants of time are identified on the graph and labeled by the letters A through F Choose the letter for the instant of time that would represent: When the vesicle is moving with the highest speed When the vesicle is moving with the slowest speed Using the graph, estimate: the average velocity of the vesicle from t = 0 to instant E The highest instantaneous velocity The slowest instantaneous velocity