GMAT Sentence Correction (SC) | Re: Scientists have recently discovered what could be the

Scientists have recently discovered what could be the largest and oldest living organism on Earth, a giant fungus that is an interwoven filigree of mushrooms and rootlike tentacles spawned by a single fertilized spore some 10,000 years ago andextending for more than 30 acres in the soil of a Michigan forest.

(A) extending
(B) extends
(C) extended
(D) it extended
(E) is extending


I thought that "extending" was making reference to the "rootlike tentacles" . Look at the statement
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