Non count noun

karthikpandian19 wrote:Built in 1913 as housing for the city's working class, the Baskerville building has a great deal more character than most modern buildings, but a lot fewer square footage, as its residents know well.

A.Built in 1913 as housing for the city's working class, the Baskerville building has a great deal more character than most modern buildings, but a lot fewer square footage, as its residents know well
B.Built in 1913 as housing for the city's working class, its residents know well that the Baskerville building has a great deal more character than most modern buildings, but a lot less square footage
C.As its residents know well, the Baskerville building has a great deal more character than most modern buildings, but a lot fewer square footage, seeing as it was built in 1913 as housing for the city's working class
D.As its residents know well, the Baskerville building has a great deal more character than most modern buildings, but a lot less square footage, seeing as it was built in 1913 as housing for the city's working class
E.Built in 1913 as housing for the city's working class, the Baskerville building has a great deal more character than most modern buildings, but a lot less square footage, as its residents know well

[spoiler]
"E" is the credited response as
"Square footage" is a non-count noun and will use "less" rather than "fewer." The correct answer will address this without introducing new errors. [/spoiler]

Can anyone explain?

GMATGuruNY wrote:

karthikpandian19 wrote:Built in 1913 as housing for the city's working class, the Baskerville building has a great deal more character than most modern buildings, but a lot fewer square footage, as its residents know well.

A.Built in 1913 as housing for the city's working class, the Baskerville building has a great deal more character than most modern buildings, but a lot fewer square footage, as its residents know well
B.Built in 1913 as housing for the city's working class, its residents know well that the Baskerville building has a great deal more character than most modern buildings, but a lot less square footage
C.As its residents know well, the Baskerville building has a great deal more character than most modern buildings, but a lot fewer square footage, seeing as it was built in 1913 as housing for the city's working class
D.As its residents know well, the Baskerville building has a great deal more character than most modern buildings, but a lot less square footage, seeing as it was built in 1913 as housing for the city's working class
E.Built in 1913 as housing for the city's working class, the Baskerville building has a great deal more character than most modern buildings, but a lot less square footage, as its residents know well

[spoiler]
"E" is the credited response as
"Square footage" is a non-count noun and will use "less" rather than "fewer." The correct answer will address this without introducing new errors. [/spoiler]

Can anyone explain?

In A and C, fewer cannot refer to footage, which is non-countable. Eliminate A and C.

In B, built incorrectly modifies residents. Eliminate B.

COMMA + VERBing should refer to the subject of the preceding clause.
In D, seeing should refer to the Baskerville building -- the subject of the preceding clause -- but clearly the building was not seeing.
While seeing as is an idiom used in conversational English, it almost certainly is not an idiom acceptable to the GMAT writers.
Eliminate D.

I'm skeptical of E. The placement of but a lot less square footage is troubling. The GMAT likely would say: the Baskerville building has a great deal more character but a lot less square footage. Also, it's not crystal clear what is being modified by as its residents know well and what exactly the residents know well. What is the source of this question?