Police officers were led to believe that many weapons sold at a certain gun store were sold illegally. Upon investigating the lead, the officers learned that all of the weapons sold by the store that were made by Precision Arms were sold legally. Also, none of the illegally sold weapons were .45 caliber.

Question

Quizplus · Accepted Answer

The second and last sentences are the two main premises in the paragraph. These two sentences give information about three categories of weapons: weapons made by Precision Arms, weapons sold legally, and .45 caliber weapons.
The last sentence states that none of the illegally sold weapons were .45 caliber. This means that none of the .45 caliber weapons were sold illegally. Notice that this new statement is a double negative. In affirmative form the statement means that all of the .45 caliber weapons were sold legally, Choice D.
The information that all of the .45 caliber weapons were sold legally (last sentence), combined with the information that all of the weapons made by Precision Arms were sold legally (second sentence), allows us to draw no valid conclusions about the relationship between the .45 caliber weapons and the weapons made by Precision Arms. There is insufficient information about the entire group of weapons sold legally to know whether the group of .45 caliber weapons and the group of weapons made by Precision Arms overlapped entirely (Choice A), partially (Choice C), or not at all (Choice B).
Choice E contradicts the second sentence and is, therefore, invalid

Police Officers Were Led to Believe That Many Weapons Sold