The passage has quite a logical information. Since pain is less at night, anesthesia used is less at night. So, risks associated with anesthesia usage could be reduced by doing surgeries at night.
I am trying to think in what situation could this not be concluded. I could just get an overview type look at the scenario and could think that perhaps, let's say, if the some risk associated with doing surgery at night happens to be much more and severe than the risk associated with giving more anesthesia during the daytime, then it will become difficult to make such a conclusion.
That's the best I could think, so I moved onto the options :
1) Well... if the energy costs are less at night, it must be good for the hospital administration. How does that get linked with the risks of surgeries happening at night or to their comparison with the risks of surgeries happening during the day. I cannot infer any link as such. This option should not be having any impact or at the max, can be a mild strengthener because it favors the conclusion only mildly, but not at all a weaken statement. Incorrect choice.
2) Are we actually talking only about baby delivery related surgeries here ? I think this choice doesn't cover the scope of the argument completely. That's the first opinion. Moreover, if more babies are born at night, how does that have any impact or relation to the risks associated with surgeries at day and at nights. Again I cannot infer any such relation. This should be an incorrect choice.
3) Okay.. so here at first I thought that may be the shift in biological rhythms might be related to the shift in response of the human body to pain at day and night. But then I thought how can I make that big a relation by myself. Biological rhythm can be anything. Again, does slight shift mean significant shift ?... in fact slight shift is for the amount of light one is exposed to sunlight..does that necessarily mean that the shift will happen in the pain bearing hormone .. certainly not.. so incorrect choice.
4) If nurses and doctors get more payment while working at night, then it sort of gives an incentive to them to work more and hard at night. May be then the risk of human performance will reduce at night. This option seems to strengthen the conclusion. So incorrect.
5) So most people lack alertness at night. Can one then say that the risk in surgeries will be less. Doesn't it look like the risk is going to weigh against the benefits of low risk against anesthesia at night. This should be the correct choice.
Correct choice E