The mayor has been accused of taking a bribe based on the fact

(A) Authorities are investigating the consultant for taking bribes from officials of other cities.
- Irrelevant
(B) The mayor was aware that many of the bills were being presented to the consultant rather than to the mayor.
- Clearly weakens Mayor's defence as the bills were being presented to the consultant rather than to mayor and mayor paid bills only presented to him
(C) The building contractor in charge of the improvements to the mayor's house had done business with the city in the past.
- Irrelevant
(D) The improvements to the mayor's house were done with expensive materials and involved thousands of hours of labor.
-Irrelevant
(E) The amount of money that the city paid the consultant over the last year greatly exceeded the cost of the improvements to the mayor's house.
- Irrelevant

Posted from my mobile device
_________________

A) "Other cities" are irrelevant to the mayor's defense
B) Correct The statement proves that the mayor knew about bills that were not charged to him. Also, this statement directly targets the mayor's defense by specifically pointing out the bills.
C) This has already been stated in the argument and is irrelevant to the mayor's defence
D) Expensive materials are out of scope
E) "The amount of money" is not a part of the mayor's defence and nor is the comparision made relevant to the conclusion.

+B
What if the mayor was presented only a little portion of the bills? B presents the loophole in mayor's claim.

Posted from my mobile device
_________________

Option E:

The amount of money that the city paid the consultant over the last year greatly exceeded the cost of the improvements to the mayor's house.

Can't this option mean that excess amount paid to consultant by city be used by consultant company for mayor's house improvement? (redirecting of money=bribe)

santosh93, this option has been crafted in a manner that makes this option the perfect trap answer. Could this option mean what you're suggesting? Perhaps, but it's hard to say. The only thing that we can conclude from this option is that if the city paid the consultant $X and the the cost of the improvements to the mayor's house is $Y, X>Y. That's it. We cannot deduce why that cost is greater and we honestly shouldn't care. In all honesty, I'd expect the money that a city pays to a consultant to be more than the cost of improving a single house.

Happy to discuss this further!

It is enticing because of the straight logical reason one may come across only to fall flat that it compares yearly payment to that of one time improvement cost.
Also, it makes us believe that it might be talking about unit rate which actually it is not.

What you are doing is making own assumption to make the option correct, an action which is always wrong.
_________________

The mayor has been accused of taking a bribe based on the fact that a consultant that does business with the city paid for improvements to the mayor's vacation house. In his own defense, the mayor has said that he paid every bill for those improvements that was presented to him.

Which one of the following, if true, most undermines the mayor's defense?

(A) Authorities are investigating the consultant for taking bribes from officials of other cities. -> Other cities is not our city's concern. Out of Scope.
(B) The mayor was aware that many of the bills were being presented to the consultant rather than to the mayor. -> If mayor know that many of the bills were being presented to the consultant rather than to him, it's a clear case of hiding facts. Let's keep it.
(C) The building contractor in charge of the improvements to the mayor's house had done business with the city in the past. -> contractor is not in our area of concern. Incorrect
(D) The improvements to the mayor's house were done with expensive materials and involved thousands of hours of labor. -> Out of scope.
(E) The amount of money that the city paid the consultant over the last year greatly exceeded the cost of the improvements to the mayor's house. -> City paid more amount than cost of the improvements to the mayor's house. How does it make mayor corrupt. Incorrect.

So, I think B.