Hi All,

I typically use the standard 3 step approach suggested by

egmat :

Meaning analysis:A substance derived from the Madagascar periwinkle, which has proved useful in decreasing mortality among young leukemia patients, is cultivated in China as part of a program to integrate traditional herbal medicine into a contemporary system of health care.

Imagine that the wheat plant is cultivated and the flour is useful for a treatment. Now flour is a derivative of the plant, can the flour be cultivated ?

Now based on this analogy lets understand the original question:

What is useful in decreasing mortality ?

The derivative

What is cultivated ?

Madagascar Periwinkle.

Error Analysis:1. "from the madagascar periwinkle, which has proved useful" --> "Which" always refer to the immediate preceding noun which in this case is the periwinkle. As per our meaning analysis "the derivative" is what is useful

2. " A substance derived from the Madagascar periwinkle,

~~which has proved useful in decreasing mortality among young leukemia patients~~, is cultivated " --> The striked out portion is providing more information about periwinkle and should be ignored to understand what is cultivated.

A substance derived, ..., is cultivated --> This is incorrect as per our analysis

Answers analysis:(A) A substance derived from the Madagascar periwinkle, which has proved useful in decreasing mortality among young leukemia patients,-->

As pointed out in the error analysis

(B) A derivative, which has proved useful in decreasing mortality among young leukemia patients, of the Madagascar periwinkle, -->

A Derivative,..., is cultivated --> Incorrect as pointed in the error analysis.(C) A Madagascar periwinkle derivative, which has proved useful in decreasing mortality among young leukemia patients,-->

Derivative is cultivated--> As pointed in the error analysis, this distorts the meaning(D) The Madagascar periwinkle has a derivative which has proved useful in decreasing mortality among young leukemia patients, that -->

"that" has a hanging precedent noun. In this statement "that" can refer to patients(E) The Madagascar periwinkle, a derivative of which has proved useful in decreasing mortality among young leukemia patients, -->

This correctly addresses the mistakes.

I hope this is helpful !

Regards,

Shradha