To Improve a Xylophone's Appearance, the Orchestra Director Decides to Have

To improve a xylophone's appearance, the orchestra director decides to have it painted. Each xylophone bar is actually a harmonic oscillator that vibrates when struck by a wooden mallet. When bending in its fundamental mode, the bar's middle and ends move in opposite directions. Painting the bar adds mass to the bar without affecting its stiffness, so the paint will

A) not affect the pitch or sound volume of the bar.
B) raise the bar's pitch.
C) lower the bar's pitch.
D) not affect the pitch of the bar, but will reduce its sound volume.