The following statements are related to the Pure Bending of beams:

1. If bending moment is constant, then the radius of curvature of the beam is constant and the shape of the elastic curve is a circular arc.

2. If bending moment is zero, then the radius of curvature of the beam is infinite and the shape of the elastic curve is a straight line.

3. If bending moment is variable, then the radius of curvature of the beam is variable and the shape of the elastic curve may be parabolic.

Which of the following statements is/are correct?