Tough CR - 1000 CR Set2 - Q12

[ranjeet_1975]

Y has been believed to cause Z. A new report, noting that Y and Z are often observed to be preceded by X, suggests that X, not Y, may be the cause of Z.
Which of the following further observations would best support the new report’s suggestion?
(A) In cases where X occurs but Y does not, X is usually followed by Z.
(B) In cases where X occurs, followed by Y, Y is usually followed by Z.
(C) In cases where Y occurs but X does not, Y is usually followed by Z.
(D) In cases where Y occurs but Z does not, Y is usually preceded by X.（A）
(E) In cases where Z occurs, it is usually preceded by X and Y.

[raunekk]

stimulus: y causes Z. X, and Y,Z follows in a sequence.That is first x then Y,Z.
New report:X and not Y cause Z.

Simple!!!Find an answer that sums up all.i.e, X causes Z and also the Sequence is followed.A sums up all the info.
B: says X occurs and then Y.Both occurs so u cannot find what causes Z.
C:X does not occur.U cannot prove that X causes Z unless X occurs.Eliminate.(This is what First Premise says.)
D:Same as in C.Z does not occur(we have to prove Z occurs) .so eliminate!!
E:It says the same thing as B.Eliminate!!

I hope this helps..

[yashesha]

A is the answer...

we jus have to find cases where Y does not occur but Z occurs...but dun forget...Y or Z should be preceeded by X