SC help

[ramsingh]

Researchers hypothesize

[theCEO]

Researchers hypothesize that granitic soil is the ideal construction material for the desert tortoise because it is not [so hard that it makes burrowing difficult or so soft that it could] cause tunnels to collapse.

(a) so hard that it makes burrowing difficult or so soft that it could

(b) hard enough to make burrowing difficult or soft enough as to cause.

Correct Answer-A

Why (b) is not the correct answer?

The use of the word "as" makes b) incorrect. Eliminating "as" would make the sentence correct.
"hard enough to make" is not parallel to "soft enough as to cause".

[GMATGuruNY]

Researchers hypothesize that granitic soil is the ideal construction material for the desert tortoise because it is not [so hard that it makes burrowing difficult or so soft that it could] cause tunnels to collapse.

(a) so hard that it makes burrowing difficult or so soft that it could

(b) hard enough to make burrowing difficult or soft enough as to cause.

Correct Answer-A

Why (b) is not the correct answer?

X enough to do Y implies that to do Y is a DESIRED OUTCOME.

John is not tall enough to play basketball.
Conveyed meaning:
To play basketball is a desired outcome for John, but he is not sufficiently tall.

B: Granitic soil is not hard enough to make burrowing difficult.
Conveyed meaning:
To make burrowing difficult is a desired outcome for the desert tortoise, but granitic soil is not sufficiently hard.
Here, the intended meaning is distorted.
Clearly, the desert tortoise does not WANT to make burrowing difficult.
Eliminate B.