Which is the result of the twisting motion of the heated helix?

Which is the result of the twisting motion of the heated helix?
 
  A) contraction of the bimetallic element B) expansion of the bimetallic element
  C) activation of the limit control switch D) activation of the emergency cut-off switch

 Q. 2

Why would a welder store welding electrodes in an oven?
 
  A) To keep them out of bad weather
  B) To hide them from other welders
  C) To prevent moisture absorption
  D) To keep them warm
  E) None of the above

 Q. 3

As the refractory temperature increases, the combustion efficiency
 
  A) increases B) fluctuates C) decreases D) stays the same