A is answer
B-Gives a reason for the bill inc
C-gives a reason
D-rate inc ..it also gives a reason
E-more usage of gas -more bill

LOL, you could see most of CR questions that like this one in GMAT exam, but I'm afraid that the score would be below 600
_________________

Certainly (A) , it doesn't talk about the potential cause of increase in gas bills..
_________________

So we're looking for possible causes of an increase in Jimmy's gas bill. The passage tells us that Jimmy's new water heater is rated as highly efficient. So we would expect the new water heater to be more efficient than the old one. In other words, if both the old heater and the new heater were used to create the same quantity of heat, the new heater should use less gas in doing so.

So, as long as the energy requirements of Jimmy's household remain constant, we would expect the gas bill to decrease.

However, we know that the gas bill increased. So we're looking for factors that could have caused this increase, such as:

• Anything that causes more gas to be used
• Anything that raises the cost of using gas

Now, let's take a closer look at (C):


This choice introduces a gas dryer to the household, which causes more gas to be used. We know the dryer is an entirely new cause of gas usage, because this choice also tells us that Jimmy was previously doing his laundry at the laundromat. That's why (C) contributes to an explanation of the increase, and that's why we eliminate the choice.

I hope that helps!
_________________