A mass is connected to the end of a spring and undergoes simple harmonic oscillation. The graph shows the position of the mass as measured from the floor as a function of time. What is the amplitude of the mass's oscillation (in units of meters)?
[Figure: Position vs. time graph for simple harmonic motion]
(A) 1.0 (B) 2.0 (C) 3.0 (D) 4.0 (E) 5.0