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Consider the following statements:        

1. Critical or whirling speed of the shaft is the speed at which it tends to vibrate violently in the transverse direction.

2. To find the natural frequency of a shaft carrying several loads, the energy method gives approximate results.

3. Dunkerley's method gives accurate results of the natural frequency of a shaft carrying several loads.

Which of these statements is/are correct? 

A) 1 only              

B) 2 and 3

C) 1 and 3            

D) 1, 2 and 3