Question about comma usage

[OneTwoThreeFour]

From OG pg. 746 #120.

A �rm that specializes in the analysis of handwriting
claims from a one-page writing sample that it can
assess more than 300 personality traits, including
enthusiasm, imagination, and ambition.

(A) from a one-page writing sample that it can
assess
(B) from a one-page writing sample it has the ability
of assessing
(C) the ability, from a one-page writing sample,
of assessing
(D) to be able, from a one-page writing sample,
to assess
(E) being able to assess, from a one-page writing
sample

Correct answer is
D

More Spoiler:
My question is on the usage of commas. Sentence D correctly uses the idiom, "claim + infinitive." But what happens if we removed the commas surrounding "from...sample"? For example, the new sentence would be:

A firm that specializes in the analysis of handwriting claims to be able from a one page writing sample to assess more than 400 personality traits...

I am assuming this is wrong now because by removing the commas, "from...sample" become a restricted prepositional phrase. Since it is restricted, the idiom, "claims to be able to" is no longer valid. Is this correct? Do rules regarding idioms always hold true when idioms have a non restrictive clause or prepositional phrase sandwiched between them? For example,

A firm that specializes in the analysis of handwriting claims, from a one page writing sample, that it can assess more than 400 personality traits.

Would the sentence above be correct too?

[Target2009]

IMO : D

[aspirant2011]

A firm that specializes in the analysis of handwriting claims, from a one page writing sample, that it can assess more than 400 personality traits................i think this would have been correct if it would have been written in the following way "A firm that specializes in the analysis of handwriting claims that it can assess more than 400 personality traits from a one page writing sample.

[Jim@Grockit]

A firm that specializes in the analysis of handwriting claims, from a one page writing sample, that it can assess more than 400 personality traits.

Would the sentence above be correct too?

Note the difference in the comma placement -- the issue is what "from a one page writing sample" is modifying. It should be modifying the assessment rather than the claim, and such should be after "that" in your hypothetical sentence.

A firm that specializes in the analysis of handwriting claims that, from a one page writing sample, it can assess more than 400 personality traits.

aspirant2011's version is still better, of course.

[OneTwoThreeFour]

Thanks for replying guys! Jim, I have one more question on your sentence:

Is the reason why the prepositional phrase modifies "it," rather than "claims," because the phrase is closest to "it" and "claims" is separated by the word "that"?

Thanks again!

[bubbliiiiiiii]

Before looking at the answer, I was stuck between C and D and finally chose C over D.

Though, I identified the correct idiom in D, I thought C is much better in terms of style.

Can someone please explain why C is wrong?

[HSPA]

D has the right parallal " to be able " "to access"

[nikhilsrl]

D appears the best choice but I think what Jim mentioned is the best way to present this sentence.