Good question - one I actually got wrong by answering E instead of D, but I understand my mistake I think and think I can answer somil -
From the word go - clearly the first sentence in first para is a conclusion - so that wipes out A and B.
Focusing on C, D and E below - clearly its not C as Para 2's boldface is rebutting the first para conclusion.
With E - which was my mistake - it's an "alternative conclusion" - in retrospect it isn't, because the first sentence in para 2 is more closer to an alternative conclusion (still not quite - it still casts doubt). When they say "it could be that xxx has lead to xxx disatisfied customers" it's more giving "evidence" (using that term loosely) to cast doubt on para 1. Hence it is D that's the right answer in reality.
Thanks for posting the question.
A)The first is evidence designed to lead to a conclusion; the second offers further evidence in support of that conclusion.
B)The first is evidence designed to lead to a conclusion; the second offers further evidence designed to cast doubt on that conclusion.
C)The first is a conclusion;the second offers evidence in support of that conclusion.
D)The first is a conclusion;the second offers evidence designed to cast doubt on that conclusion.
E)The first is a conclusion;the second is an alternative conclusion based on the same evidence