All of the following conclusions are based upon accurate expense vouch

Hi Tonglin,

First the answer...i believe it should be B.

Here is what i could make out of the question...

There is this company and it's employees submitted vouchers to the department heads in 1995. What ever they submitted is "accurate". Now at a later date some additional vouchers are discovered. This discovery will affect the original conclusions and might weaken some of them. Let's take one example of choice A.

"The accounting department had only 15 employees and claimed expenses of at least $500"

Here is the newly found vouchers were submitted by another employee (not among these 15) then this conclusion was wrong --> The number of emplyees was infact more than 15. Same is the case with all the other choices, except B.

Since be says "there were atleast 25 employees" and that the total expense was atleast $35,000 --> this conclusion is un-affected by the newly found vouchers, no matter who submitted them and for what ever amount.

HTH