SC 1000 vs. OG: redundancy

I was left with D & E. I noticed a small difference after reading closely.
I chose 'D'

I eliminated 'E' as it says practice can cause errors
IMO The practice does not cause error itself. However, The practice can have the potential to cause errors

But according to OG, "can potentially" is redundant (Q-159, OG-10 );

I am quite dazed after reading this
Can you post full information provided in OG10 regarding how 'can potentially' become redundant?

satishchandra wrote:I was left with D & E. I noticed a small difference after reading closely.
I chose 'D'

I eliminated 'E' as it says practice can cause errors
IMO The practice does not cause error itself. However, The practice can have the potential to cause errors

But according to OG, "can potentially" is redundant (Q-159, OG-10 );

I am quite dazed after reading this
Can you post full information provided in OG10 regarding how 'can potentially' become redundant?

159. While depressed property values can hurt some
large investors, they are potentially devastating for homeowners.
whose equity--in many cases representing a life's
savings--can plunge or even disappear.
A) they are potentially devastating for
homeowners, whose
B )they can potentially devastate homeowners in i.
that their
C )for homeowners they are potentially devastating,
because their
D )for homeowners, it is potentially devastating in
that their
E)it can potentially devastate homeowners, whose
Choice A is the best. Its wording is unambiguous and
economical. The plural pronoun they agrees with its
antecedent, property values. The pronoun whose clearly
refers to homeowners and efficiently connects them with the
idea of lost equity. In B, C, and D, substituting in that their
or because their for whose is wordy and confusing since the
antecedent of their might be they, not homeowners.
Furthermore, can potentially is redundant in B and E. Both D
and E use the singular pronoun it, which does not agree with
its logical antecedent, property values.

Even I think, there is a mistake in SC-1000. It should be D.

Thanks.