Complete Question Explanation
(The complete setup for this game can be found here: viewtopic.php?t=17159)
The correct answer choice is (E)
If Z is selected, then from the third rule W is not selected. If W is not selected, then from the contrapositive of the fourth rule M is not selected. Thus, answer choices (A), (B), and (C), each of which contain M, are wrong.
Answer choice (D) is incorrect because it would result in an insufficient number of stones to make the six rings. If no ruby is selected, then all three sapphires must be selected. However, that means that M is selected, which from the fourth rule forces W to be selected. Since Z is already selected according to the question stem, this results in a violation of the third rule.
Answer choice (E) can be confirmed by the following hypothetical: X–Y–Z–F–G–H.