a.
Cu
wire at 30∘C
will conduct more electricity since conductance in metals is inversely proportional to temperatue. With the increase in temperature, metallic conductance decrease due to the vibration of positive fixed kernals.
b.
KBr
solution at 60∘C
, because conductance of a strong electrolyte is directly proportional to the temperature due to the increase in ionic mobilities.
c.
NH4OH
solution at 60∘C
, because the conductance of a weak electrolyte is also direactly proportional to temperature due to increase in ionization.
d.
0.1M
propanoic acid solution , because the conductance of a weak electrolytic is inversely proportional to concentration or directly proportional to dilution due to increase in ionization on dilution.