OE:
Identify the Question
The prompt asks for a statement that "strongly supports" the conclusion, so this is a Strengthen question.
Deconstruct the Argument
In the passage, the instructor states that sewing leather is in some ways easier than sewing fabric, and provides two specific ways in which that statement is true. The instructor then concludes, unexpectedly given the facts just stated, that beginning sewers should nonetheless acquire mastery with fabric before switching to leather. No reasons are provided for why fabric is better for beginners.
State the Goal
Right now, the instructor's argument is not actually an argument, as there are no statements supporting the contention that fabric is better than leather for beginners. Therefore, to strengthen the argument -- or, perhaps more accurately, to create an argument in the first place -- we need at least one reason why fabric is more appropriate than leather for beginning sewers. Notice that the desired statement must satisfy two conditions. First, it must describe an advantage of fabric over leather; second, it must apply specifically, or especially, to beginners.
Work from Wrong to Right
(A) The fact that this attachment must be purchased separately may present a minor inconvenience, but because it is inexpensive, this is not a major deterrent. (If the attachment were expensive, then this statement would provide some support for the argument, as it would be inadvisable for beginners to spend a great deal on a new hobby until achieving a certain level of competence.)
(B) While this may be true, this choice provides no reason why it would be better for beginners to learn how to sew using fabric even though there are at least two reasons why it's easier to sew leather.
(C) Although this statement suggests that fabric may, in general, be more versatile than leather, it provides no support for the idea that fabric is more appropriate for beginning sewers.
(D) CORRECT. This statement provides a concrete advantage of fabric in the case of sewing errors; namely, incorrect stitches can be removed from fabric, but not from leather, without leaving visible evidence. Moreover, it may reasonably be assumed that beginners make mistakes more frequently than other sewers, so issues regarding errors are of particular concern to beginners. This choice thus supports the instructor's argument.
(E) This choice explains another advantage of leather over fabric, and so is exactly the opposite of what is needed.