The answer is C as per the last sentence of the premise. This is a classic question that highlights how important it is to pay attention to single words as they can change the meaning of the answer choice.

At the end, the author states that , using the dull companion gives readers a chance to solve the mystery while also diverting them from the correct solution.

Answer choice C states - SOME mystery novels give readers enough clues to get the correct solution to the mystery,

The word 'some' here is what makes C correct. It is not extreme and is in line with the closing sentence.

Answer choice A is a tempting one but pay attention to the language. The author starts of by saying most stories OFTEN feature a brilliant detective. However, in choice A, the answer choice states MOST mystery stories feature a brilliant detective.

There is a difference between most and often in that, often does not refer to a majority of the times as most does.

Example: If you go to the mall 3 times a week, you can say, i often go to the mall. You cannot say ' i go to the mall MOST days of the week as going most days of the week would require you to go 4+ days.

Choice C uses the weasel word 'some' implying a few books do give the reader clues to deduce solutions to the mystery which is in line with the closing statement.

Let me know if you picked an answer choice other than A

@ Ravish: I eliminated B, D & e. However, I had this confusion on correlating OFTEN, MOST and SOME...THanks for clarifying.