Although the fear last year that .......Veritas tricky SC

[Mo2men]

Although the fear last year that the trade zone might break apart had receded, the risk now could be prolonged stagnation of the kind that has plagued Argentina for the past two decades.

A.had receded, the risk now could be prolonged stagnation of the kind that has plagued Argentina for the past two decades

B.had receded, the risk now could be prolonged stagnation as it has plagued Argentina for the past two decades

C.receded, the risk now could be prolonged stagnation, just as it has plagued Argentina for the past two decades

D.has receded, the risk now could be prolonged stagnation, like it has plagued Argentina for the past two decades

E.has receded, the risk now could be prolonged stagnation, like that which has plagued Argentina for the past two decades

Source: Veritas

OA: E

Dear Mitch,

1- Why C is wrong? is the construction 'just as' is wrong? Is the past tense verb correct?

2- In OA, is the construction ' that which' is right? Does not GMAT consider 'which' a non-essential modifier can hence need to be preceded with 'comma'?

Thanks

[GMATGuruNY]

Although the fear last year that the trade zone might break apart had receded, the risk now could be prolonged stagnation of the kind that has plagued Argentina for the past two decades.

A.had receded, the risk now could be prolonged stagnation of the kind that has plagued Argentina for the past two decades

B.had receded, the risk now could be prolonged stagnation as it has plagued Argentina for the past two decades

C.receded, the risk now could be prolonged stagnation, just as it has plagued Argentina for the past two decades

D.has receded, the risk now could be prolonged stagnation, like it has plagued Argentina for the past two decades

E.has receded, the risk now could be prolonged stagnation, like that which has plagued Argentina for the past two decades

Source: Veritas

OA: E

Dear Mitch,

1- Why C is wrong? is the construction 'just as' is wrong?

Generally, as serves to compare VERBS.
C: The risk now could be prolonged stagnation, just as it has plagued Argentina for the past two decades.
Here, as serves to compare the two verbs in red.
It is illogical to compare a STATE-OF-BEING (could be) to an ACTION (has plagued).
Eliminate C.

Is the past tense verb correct?

C: The fear last year that the trade zone might break apart receded.
Here, it is illogical to attribute a PAST ACTION -- receded -- to a CURRENT FEAR (that the trade zone might break apart).
Eliminate C.

2- In OA, is the construction ' that which' is right? Does not GMAT consider 'which' a non-essential modifier can hence need to be preceded with 'comma'?

The OA conveys the following meaning:
The risk now could be prolonged stagnation, like the prolonged stagnation that has plagued Argentina for the past two decades.
To avoid repetition, the phrase in blue is replaced with the copy pronoun that:
The risk now could be prolonged stagnation, like that that has plagued Argentina for the past two decades.
The result is the confusing construction in blue and red: that that.
When a comparison results in that that, we replace the second that with which:
The risk now could be prolonged stagnation, like that which has plagued Argentina for the past two decades.
The construction in green is correct.
While that which is a valid construction, I cannot cite an OA that has employed this construction.