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?

Following figures show the arrangement of bar magnets in different configurations. Each magnet has magnetic dipole $\overrightarrow{m}$. Which configuration has highest net magnetic dipole moment?

(a)(b)(C)(d)

Hysteresis loops for two magnetic materials $A$ and $B$ are given below:

(A)(B)

These materials are used to make magnets for electric generators, transformer cores and electromagnet cores. Then it is proper to use