pronouns other than we, our and I always have an antecedent?

Hi,

Great question! Pronouns require antecedents, so you are absolutely correct that in (E), we have no antecedent for "they." Who are "they"? We have no idea.

The other major error in (E) is the incorrect addition of the comma before the preposition "from."

The GMAT does not explicitly test punctuation, but it is true that unnecessary commas often break up the "flow" of the sentence and add awkwardness to the construction. Shorter answer choices are not something the GMAT explicitly tests either, but it's amazing to notice how often shorter choices are correct! Likewise, many incorrect GMAT SC choices contain unnecessary commas.

When we have a introductory prepositional phrase that is acting like an adverb (modifying the action of the sentence), we set it apart with commas.

(CORRECT) EX: From Paris to London, the Chunnel train sped rapidly along.

But it becomes unnecessary to put a comma before it when it goes at the end of the sentence:

(INCORRECT) EX: The Chunnel train sped rapidly along, from Paris to London.
(CORRECT) EX: The Chunnel train sped rapidly along from Paris to London.

If the prepositional phrase was acting like an adjective (modifying the NOUN), we would put commas both after and before it.

(CORRECT) EX: Of Parisian birth, my father speaks excellent French.
(CORRECT) EX: My father, of Parisian birth, speaks excellent French.

Anyway, long story long, the GMAT does not like unnecessary commas. Do not select a choice with a comma unless that comma serves a purpose and is REQUIRED.

Here, "from his garden" is an adverbial phrase because it modifies "had just been picked," a verb. No comma is needed.