Which of the following is desirable for making permanent magnets?

Curie temperature is the temperature above which

The Curie temperature $T_{C}$ represents:

The magnetic susceptibility is negative for

There are four light-weight rod samples $A, B, C, D$ separately suspended by threads. $A$ bar magnet is slowly brought near each sample and the following observations are noted:
$(i)$ $A$ is feebly repelled
$(ii)$ $B$ is feebly attracted
$(iii)$ $C$ is strongly attracted
$(iv)$ $D$ remains unaffected
Which one of the following is true?

Why is steel suitable for making permanent magnets?