Which type of magnets are used in extremely fast trains that run on magnetic levitation?

The variation of magnetic susceptibility $(\chi )$ with temperature for a diamagnetic substance is best represented by:

Which of the following statements are correct?
$(A)$ Electric monopoles do not exist whereas magnetic monopoles exist.
$(B)$ Magnetic field lines due to a solenoid at its ends and outside cannot be completely straight and confined.
$(C)$ Magnetic field lines are completely confined within a toroid.
$(D)$ Magnetic field lines inside a bar magnet are not parallel.
$(E)$ $\chi = -1$ is the condition for a perfect diamagnetic material,where $\chi$ is its magnetic susceptibility.
Choose the correct answer from the options given below:

Any magnetic material loses its magnetic property when it is

Above the Curie temperature,the susceptibility of a ferromagnetic substance varies

When a ferromagnetic material is heated to a temperature above its Curie temperature,the material