Question

Directions for questions 37 to 41: Analyze the statements given and provide an appropriate answer for the questions that follow.

The number of airplanes equipped with a new anti-collision device has increased steadily during the past two years. During the same period, it has become increasingly common for key information about an airplane's altitude and speed to disappear suddenly from air traffic controllers' screens. The new anti-collision device, which operates at the same frequency as air traffic radar, is therefore responsible for the sudden disappearance of key information.

Which one of the following, if true, most seriously weakens the argument above?

• A. The new anti-collision device has already prevented a considerable number of mid-air collisions.
• B. It was not until the new anti-collision device was introduced that key information first began disappearing suddenly from controller's screens.
• C. The new anti-collision device is scheduled to be moved to a different frequency within the next two to three months.
• D. Key information began disappearing from controller's screen three months before the new anti-collision device was first tested.

Hint:

Look for the option that breaks the timeline the argument depends on, for example a fact showing the effect started before the supposed cause existed.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The argument says the new anti-collision device is responsible for key flight information disappearing from radar screens, because both trends rose over the same two years and the device shares a frequency with air traffic radar. We need the option that most seriously weakens this causal claim.

Step 2: Key Formula or Approach:
An argument that says two things happened together, so one caused the other, is weakened most by showing the timing does not fit, for example if the effect started before the supposed cause existed, or by showing another cause is more likely.

Step 3: Detailed Explanation:
Option 4 says key information began disappearing from controllers' screens three months before the new anti-collision device was even first tested. If the disappearing information started before the device existed in any working form, the device cannot be the cause of that first wave of disappearances, this directly breaks the timeline the argument depends on and is the strongest weakener.
Option 1 says the device has already prevented mid-air collisions. This speaks to whether the device is useful, not to whether it also causes screen interference, so it does not weaken the causal claim.
Option 2 says the disappearances only began after the device was introduced. This actually strengthens the timing link the argument is built on, it is not a weakener.
Option 3 says the device is scheduled to move to a different frequency in future months. A future change does not tell us whether the current frequency overlap is the cause of the current problem, so it does not weaken the argument about the past two years.
Option 5, dropped in the folded version, said the disappearances happened only at large airports. This is a detail about where the problem shows up, it does not rule out the device as the cause, since large airports could simply have more of these devices in use.

Step 4: Final Answer:
The argument is weakened most by the fact that the disappearances began three months before the device was first tested, option 4.