Which one of the following sets of readings (potential difference in V, current in A) could belong to a metallic wire maintained at constant temperature?
a) (5,0.25);(10,0.55);(15,0.75)
b) (3,0.12);(6,0.24);(9,0.40)
c) (2,0.10);(4,0.20);(6,0.30)
d) (2,0.10);(4,0.19);(6,0.27)