Kate San's study, published in Nature,

[paes]

Kate San's study, published in Nature, shows that the ancients lined up the pyramids with two stars whose alignment was only true around 4,500 years ago,which makes it possible to improve the margin of error in the archaeological chronology of ancient Egypt, from plus or minus 100 years to only five years, which makes it possible to pinpoint what people probably think was the start of construction of Khufu's Great Pyramid at Giza to around the year 2467 BC.

A) which makes it possible to improve the margin of error in the archaeological chronology of ancient Egypt, from plus or minus 100 years to only five years, which makes it possible to pinpoint what people probably think was the start

B) which makes it impossible to stick to the margin of error in the archaeological chronology of ancient Egypt, which was plus or minus 100 years in favor of one which is only five years, pinpointing the probable start

C) suggesting that the margin of error for the archaeological chronology of ancient Egypt is no longer plus or minus 100 years, but rather only five years, which suggests the possibility of pinpointing the probable start

D) making improvements in the margin of error in the archaeological chronology of ancient Egypt, from plus or minus 100 years to only five years, pinpointing the probable start

E) making it possible to improve the margin of error in the archaeological chronology of ancient Egypt, from plus or minus 100 years to only five years, pinpointing the probable start.

[spoiler]OA later
I am stuck between D and E.
I am unable to understand the meaning of it ( making it possible) in E, somebody please explain
[/spoiler]

[uwhusky]

I think it's E. I believe D has a modifier error by suggesting the clause "shows that the ancients lined up the pyramids with two stars whose alignment was only true around 4,500 years ago" is making the improvements, yet the subject is Kate San's study that's making the improvements. So I believe that the pronoun "it" is required, and also I believe the active voice in E is preferred over passive voice in D.

D: "making improvements in the margin of error"
E: "making it possible to improve the margin of error"

[paes]

OA is E. Thanks

Can you more elaborate the function of it here.

I am not seeing any antecedent for 'it'.
Then what type of usage is it ?

[pnk]

it in E - placeholder IT (MGMAT)

Can someone explain - what 'pinpointing' modify

[ankur1347]

D & E are the probable choices based on grammatical structure

E is better as the original sentence has some uncertainty in the word "possible" but in D its more of certain.

Hence E is correct