ancient Inca city

[akhp77]

Source: Manhattan GMAT Q Bank

The ancient Inca city of Macchu Picchu, perched on a ridge in the Andes Mountains of Peru, had been built at a high enough altitude that it often makes modern-day tourists from lower elevations sick with oxygen deprivation.

A: had been built at a high enough altitude that it often makes modern-day tourists from lower elevations sick with oxygen deprivation
B: had been built at so high of an altitude that it often makes modern-day tourists from lower elevations sick from oxygen deprivation
C: was built at a high enough altitude that modern day tourists from lower elevations often become sick with oxygen deprivation when visiting the city
D: was built at such a high altitude that modern-day tourists from lower elevations often become sick from oxygen deprivation when visiting the city
E: was built at so high of an altitude that it often makes modern-day tourists from lower elevations sick from oxygen deprivation

OA: D
I confused over C and D.
"sick from" is correct idiom.

What is the difference between "high enough altitude" and "such a high altitude" in context of usage and meaning?

[tim]

You could talk about such a high altitude that something happens, but you could talk about a high enough altitude to do something. C doesn't reflect this usage, which is another reason it's wrong in addition to the other idiom you identify..

[akhp77]

Can you please an easy example for each one?

It would be easy to understand better.

[tim]

The summit of Mount Everest is at such a high altitude that trees cannot grow there..

The summit of Mount Everest is at a high enough altitude to prevent trees from growing..

Does this help?

[ameya]

First of all, sorry to bump the old thread but I am confused with the OA. Isn't adding "when visiting the city" make sentence redundant? This phrase is not there in the original sentence.

Ameya

[tim]

no it's not redundant; in fact, it helps clarify when tourists get sick..