Sentence Correction

New theories propose that catastrophic impacts of asteroids and comets may have caused reversals in the Earth's magnetic field, the onset of ice ages, splitting apart continents 80 million years ago, and great volcanic eruptions.

(A) splitting apart continents
(B) the splitting apart of continents
(C) split apart continents
(D) continents split apart
(E) continents that were split apart

I picked the correct answer
But,I have a confusion between option A and B.
If -ing is prefixed with is/are/am then it acts as a verb.
So,why in option A we treat SPLITTING APART CONTINENTS as VERB.
Please clarify.

prabsahi wrote:New theories propose that catastrophic impacts of asteroids and comets may have caused reversals in the Earth's magnetic field, the onset of ice ages, splitting apart continents 80 million years ago, and great volcanic eruptions.

(A) splitting apart continents
(B) the splitting apart of continents
(C) split apart continents
(D) continents split apart
(E) continents that were split apart

I picked the correct answer
But,I have a confusion between option A and B.
If -ing is prefixed with is/are/am then it acts as a verb.
So,why in option A we treat SPLITTING APART CONTINENTS as VERB.
Please clarify.

Option A is wrong on 2 parts:
1. This is not following the rule of parallelism.
reversal in the .... (noun)
the onset of ice ages.... (noun)
great volcanic eruptions.... (noun)

the answer choice needs a noun/noun phrase. Without changing the meaning of the sentence [spoiler](B)[/spoiler] is the correct answer.

2. Your are right by saying "If -ing is prefixed with is/are/am then it acts as a verb"
Splitting apart continents is indicating a verb and it is missing the word "is".
However if the word "is" was included, this would still be breaking the rule of parallelism.

An alternative approach is to strip the sentence of all the unnecessary words and see which choice sounds right, for example

condensed sentence: Impacts of asteroids caused....
1. reversals in the Earth's magnetic field,
2. the onset of ice ages,
3. great volcanic eruptions

(A) splitting apart continents
(B) the splitting apart of continents
(C) split apart continents
(D) continents split apart
(E) continents that were split apart

a) Impacts of asteroids caused splitting apart continents.
This option does not sound right and is also structured incorrectly.