Two identical metallic wires, X and Y, are connected in separate circuits. Wire X is kept in an ice bath so its temperature stays nearly constant, whereas wire Y is allowed to heat up while current flows. Which statement about their V–I characteristics is correct?
a) Both X and Y will show straight lines passing through the origin
b) X will show a straight line through the origin, while Y will show a curve bending downward
c) X will show a straight line through the origin, while Y will show a curve bending upward
d) X will show a curve bending upward, while Y will show a straight line through the origin