Critical Reasoning

Q1: Researchers have recently discovered that approximately 75% of restaurant lemon wedges they studied were contaminated with harmful microorganisms such as bacteria and fungal pathogens. The researcher looked at numerous different restaurants in different regions of the country. Most of the organisms had the potential to cause infectious disease. For that reason, people should not order lemon wedges with their drinks. Which of the following, if true, would most weaken the conclusion above?

a)The researchers could not determine why or how the microbial contamination occurred on the lemon wedges
b)The researchers failed to investigate contamination of restaurants lime wedges by harmful microorganism
c)The researchers found that people who ordered the lemon wedges at restaurants were equally likely to contract the disease cause by the discovered bacteria as were people who did not order lemon wedges
d)Health laws require lemons to be handled with gloves or tongs, but the common practice for waiters is to handle them with their bare hands

e)Many factors affect chance of an individual contracting a disease by coming into contact with bacteria that have nothing to do with lemons. These factors include things such as health and age of the individual, as well as the status of their immune system

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Q2: Heavy consumption of alcohol causes impaired judgement, a loss of fine motor skills, slower reaction time, a decrease in visual acuity, and other short-term symptoms. Since alcohol can be metabolized in the average person's body at a rate of 0.015BAC (or Blood alcohol content) per hour, a severely intoxicated individual with a BAC of 0.15 should be symptoms-free after 10 hours. After this time, if the individual exhibits similar symptoms, such symptoms cannot be caused by alcohol. Which of the following, if true, would most weaken the conclusion above?

a)Some symptoms normally associated with alcohol consumption may resemble symptoms caused by prescription drugs or even drowsiness
b)Increase in BAC are based off of the amount of alcohol consumed, not the number of drinks (some drinks contain more alcohol than others)
c)Heavy alcohol consumption has numerous long-term effects such as cirrhosis of the liver, and birth defects
d)The metabolization rate of alcohol varies depending upon a person's health, weight, diet, and genetic predispositions
e)Some people, due to an acute sensitivity to alcohol, cannot even reach a BAC of 0.15 before becoming violently ill.
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My doubt: in Q1, The argument says "Restaurant lemon wedges are contaminated with microorganisms that can cause disease, and therefore, people should not order lemon wedges". Option E talks about many other factors that can determine whether a person will get affected with microorganisms in lemon wedges or not? If there are many other unknown factors why would one suggest people to avoid ordering lemon wdges? But we know C is better than E

Q2: while in Q1 we ignored choice E talking about other factors that can have determine whether person will get infected or not, in Q2 we accept a choice (ie D) that lists unknown factors weakening the conclusion. Why in Q1 E is a bad choice while in Q2 D is a good choice - though both choices list some factors (not mentioned in the argument).

Will appreciate your response.

Source: Veritas; [spoiler]OA - (1) C; (2) D[/spoiler][/spoiler]