The data collected by weather airplanes that fly into the heart of a

A & D are wrong for the use of "their" to refer the storm. D is wrong since "and not for" is needed to maintain the parallelism. Between B & E, E seems correct because B uses "the speed and path" where as it should be "the speed and the path" to refer the spped and path seperately.

The data collected by weather airplanes that fly into the heart of a hurricane are useful mainly for gauging the storm’s structure and strength, not for the speed and the path of their movement.
(A) not for the speed and the path of their movement
(B) not for the speed and path of its movement
(C) not the speed and path of its movement
(D) and not the speed and path of their movements
(E) and not for the speed and the path of its movements

Is 'and' not required in option C ? as ',and not the speed and path of its movement.'

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Clause + item1 and item2.

Whenever we have 'and' in the sentence, the sentence should make sense when read independently-
Clause + item1 and clause + item2

Read now
the data..are useful mainly for gauging the storm’s structure and strength,
the data ...are useful mainly for gauging not the speed and the path of its movement. ----> doesn't make sense. So, usage of and is wrong here.

The data collected by weather airplanes that fly into the heart of a hurricane are useful mainly for gauging the storm’s structure and strength, not for the speed and the path of their movement.

The question has been answered multiple time, but let's not focus on grammar, parallelism and other GMAT trick, and try to analyse the question entirely from meaning perspective one more time with me.

Analysis 1:

The data collected by weather airplanes that fly into the heart of a hurricane are useful mainly for gauging the storm’s structure and strength, not for the speed and the path of their movement.

Let's focus on non-underlined portion -
The data are useful for SOMETHING - we need to figure out what is that SOMETHING now.

That SOMETHING is "gauging/measuring/calculating the storm’s structure and strength, not gauging/measuring/calculating the speed and the path

Hence, The data are useful for gauging the storm’s structure and strength, not the speed and the path

Analysis 2:

The data collected by weather airplanes that fly into the heart of a hurricane are useful mainly for gauging the storm’s structure and strength, not for the speed and the path of their movement.

Let's focus on non-underlined portion -
The data are useful - now we need to see what comes after useful.

If we consider the first part where "data are useful FOR gauging the storm’s structure and strength", in the second part we should write - "data are not useful FOR <GAUGING/MEASURING/CALCULATING> the speed and the path".

Logically and considering the meaning, it doesn't make sense that data can be used for the speed and the path directly. Data can be used only to ESTIMATE/GAUGE/CALCULATE the speed and path, the way data was used to ESTIMATE/GAUGE/CALCULATE structure and strength.

Hence, I would go ahead with my analysis 1 and answer choice C.

Thanks and please help to improve this (if my logic is incorrect).

In C where is the antecedent for “its”
Storm’s is not a correct antecedent

sacmanitin, ChrisLele

Hi,

The data collected by weather airplanes that fly into the heart of a hurricane are useful mainly for gauging the storm’s structure and strength, not for the speed and the path of their movement.

I think it should be "is" instead of "are", since it is referring to the subject The data.

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