A) (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
B) (a)-(iv), (b)-(i), (c)-(ii), (d)-(iii)
C) (a)-(iii), (b)-(i), (c)-(ii), (d)-(iv)
D) (a)-(i), (b)-(ii), (c)-(iv), (d)-(iii)
Explanation
[Solution] $MgH_2$ is ionic (saline), $GeH_4$ electron precise, $B_2H_6$ electron deficient and HF electron rich. Answer (2).