Whichof the following, if true, most seriously weakens the argument?
(A) There are many different strains of the E. coli bacteria, and only some of these strains are harmful.
(B) Some types of bacteria found in sewage are neither disease-causing nor difficult to detect
directly.
(C) Some of the types of bacteria found in sewage along with E. coli are not harmful to people
unless the bacteria are ingested in large quantities.
(D) E. coli dies out much more quickly than some of the more harmful bacteria found in sewage and then can no longer be easily detected.
(E) Some of the types of bacteria found in sewage along with E. coli reproduce at a slower rate
than E. coli.
Questions 12-17
A bank has exactly four cashier windows, arranged in a row and numbered consecutively 1through 4 from one end of the row to the other. The bank has exactly six cashiers: two supervisors (Joan and Karim); and four trainees (Lorraine, Mark, Nora, and patrick). Throughout a particular peak-hour period, the stationing of cashiers at windows is restricted as follows:
There must be exactly one cashier at each window.The cashier at window 2 must be a supervisor.
Lorraine must be at a window but cannot be at window 3. If Mark is at one of the windows, Joan must be at a window immediately adjacent to it. The cashiers at the windows must include either Nora or Patrick, but they cannot include both Nora and Patrick.
12.Which of the following lists the cashiers who can be stationed at windows 1 through 4 during this period?1 2 3 4
(A) Joan Karim Mark Lorraine
(B) Joan Karim Nora Lorraine
(C) Karim Nora Joan Lorraine
(D) Mark Joan Lorraine Patrick
(E) Patrick Joan Nora Lorraine
13.Which of the following must be true about the stationing of the cashiers during this period?
(A) Joan is at window 1 orat window 2.
(B) Karim is at window 2 or at window 4.
(C) Lorraine is at window 1 or window 4.
(D) Nora is at window 1 or at window 3.
(E) Patrick is at window 3 or at window 4.