For more insight on this really tough question (and to uncloud any issues that may exist), here's a similar one from OG:
OG15 132:
132. Although appearing less appetizing than most of their round and red supermarket cousins, heirloom tomatoes, grown from seeds saved during the previous year—they are often green and striped, or have plenty of bumps and bruises—heirlooms are more flavorful and thus in increasing demand.
(A) Although appearing less appetizing than most of their round and red supermarket cousins, heirloom tomatoes, grown from seeds saved during the previous year
(B) Although heirloom tomatoes, grown from seeds saved during the previous year, appear less appetizing than most of their round and red supermarket cousins
(C) Although they appear less appetizing than most of their round and red supermarket cousins, heirloom tomatoes, grown from seeds saved during the previous year
(D) Grown from seeds saved during the previous year, heirloom tomatoes appear less appetizing than most of their round and red supermarket
cousins
(E) Heirloom tomatoes, grown from seeds saved during the previous year, although they appear less appetizing than most of their round and red supermarket cousins
OE:
Rhetorical construction; Grammatical construction
The intended meaning could be communicated more effectively by mentioning heirloom tomatoes as early as possible in the sentence, so that we know that the writer is comparing heirloom tomatoes with supermarket tomatoes. The placement of heirloom tomatoes and heirlooms makes the sentence ungrammatical.
A This is ungrammatical. If heirloom tomatoes is the subject of are more flavorful … then heirlooms has no predicate and is nonsensically superfluous. If heirlooms is the subject, heirloom tomatoes has no predicate.
B Correct. The noun heirloom tomatoes is mentioned early in the sentence, followed by a parenthetical definition, and is the subject of the verb appear, and heirlooms is the subject of are.
C The noun heirloom tomatoes appears too late in the sentence. Parsing is made harder by introducing the pronoun they and revealing its antecedent later in the sentence. The sentence is also ungrammatical. If heirloom tomatoes is the subject of are more flavorful … then heirlooms has no predicate and is nonsensically superfluous. If heirlooms is the subject, heirloom tomatoes has no predicate.
D Beginning the sentence with the explanatory clause grown from seeds … gives it too much importance. It could be construed as the reason why heirloom tomatoes appear less appetizing, which is contrary to the truth. The sentence is also ungrammatical.
E Rhetorical structure requires that although appear in the beginning of the clause to which it pertains. Placing it later necessitates the pronoun they with antecedent heirloom tomatoes, which is redundant. The sentence is also ungrammatical.
The correct answer is B