a+ib<=c+id is a meaningful only whena) a2+c2=0b) b2+c2=0c) b2+d2=0d) a2+d2=0

hi,

  we can, t compare two complex no. . there is no such concept . comparison will be possible only if both the no. are real.

means   b as well as d  is equal to zero. means

c) b²+d²=0