For help about sc

210. 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 and extending for more than 30 acres in the soil of a Michigan forest.

(A) extending

(B) extends

(C) extended

(D) it extended

(E)  is extending

Choice A, the best answer, preserves grammatical parallelism while allowing for logical expression of temporal relation­ships; A employs the parallel participial phrases spawned... and extending ... to modify filigree. Other choices present different grammatical constructions that are not participial modifiers and thus not parallel to spawned: extends in B is a present-tense verb; it extended in D begins a new clause; and is extending in E ungrammatically introduces a new predicate. In C, extended is nonparallel if it is assumed to be a past tense verb form; if it is assumed to be a past participle, it illogically states, as does D, that the filigree extended only in the past.