A 600 Cm Long Brass Rod Is Suspended at the Ends

A 60.0 cm long brass rod is suspended at the ends by long strings. The rod is struck at one end parallel to the rod and causes the rod to vibrate longitudinally with the ends free. (Y = 9.00 × 10¹⁰ N/m², density = 8,470 kg/m³.) Assuming the rod vibrates in its fundamental mode, the frequency of the vibration is

A) 3,790 Hz.
B) 3,540 Hz.
C) 3,120 Hz.
D) 2,720 Hz.
E) 2,140 Hz.