A reasonable hypothesis would be that, nothing changes with can A (no expansion at all), and Can C is expanding, but Can B is expanding even faster than Can C. (I don't know, if this hypothesis is correct though)
Answer:
I dont either but I'm sorry and hopefully you figured it out
Elements with low specific heat values tends to absorb heat energy lesser which means it will heat up faster. Having low specific heat values means it can have rapid changes in temperature. Metals generally have a low specific heat capacity, that's why their temperature can change so quickly.