@JayDee8732 the problem with (D) is that we do not know that "some nectarine trees that are not labeled 'miniature' are labeled incorrectly."
All we know is that, "While some nurseries label any nectarine trees of the Stark Sweet Melody variety as 'miniature,' for example, others do not." Whether this is correct or incorrect is never addressed.
We are given a principle that tells us when this label is correct, but we are not provided with the information to invoke it for Stark Sweet Melody variety of nectarine tree.
Compare that with (E), "Unless the Stark Sweet Melody variety of nectarine tree is suitable for growing in a tub or a pot, some nurseries mislabel this variety of tree."
This is a conditional statement invoking the principle set forth in the last sentence of the stimulus, i.e. "if a variety of fruit tree is not suitable for growing in a tub or pot, no tree of that variety can be correctly labeled 'miniature.'"
not SGTP ==> not CLM CLM ==> SGTP
We know that some nurseries label nectarine trees of the Stark Sweet Melody variety as "miniature" so if they are not suitable for growing in a tub or pot, this label would be incorrect (i.e. not SGTP ==> not CLM).
So (E) is directly supported by the information in the stimulus and it would be the correct answer.
Hope that helps! Please let us know if you have any other questions.
