Sentence Correction

Geologists once thought that the molten rock known as lava was an underground remnant of Earth's earliest days, sporadically erupting through volcanoes, but they now know that it is continuously created by the heat of the radioactivity deep inside the planet.
A)was an underground remnant of Earth's earliest days, sporadically erupting
B)had been an underground remnant of Earth's earliest days and sporadically erupted
C)was an underground remnant of Earth's earliest days, which sporadically erupted
D)would be an underground remnant of Earth's earliest days that sporadically erupted
E)was an underground remnant of Earth's earliest days, having sporadically erupted


[spoiler]
(A) CORRECT. This choice is correct as it repeats the original sentence.



(E) In this choice, "having sporadically erupted" incorrectly places this modifier in the past tense, implying that lava no longer erupts through volcanoes.[/spoiler]

MGMAT uses outside information that lava still erupts through volcanoes. Is it correct to use out side information to solve outside problems .

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Guys i have the OA . Please refrain from replying with IMO A/B/C/D/E . Please reply in case you are able to explain .
Thanks a Lot