Nearly two tons of nuclear-reactor fuel have already been put into orbit around the Earth, and the chances of a collision involving such material increase greatly as the amount of both space debris and satellites continue to rise.

A. as the amount of both space debris and satellites continue to rise
B. as the rise continues in both the amount of satellites and space debris
C. as the amount of space debris and the number of satellites continue to rise
D. with the continually increasing amount of space debris and the number of satellites
E. with the amount of space debris continuing to increase along with the number of satellites

I agree with the OA.
However, I have two doubts:
a) In D and E, what is wrong with "with"? Is there a change in meaning?
b) Is "amount of" always singular or does it depend on the noun that is acting as object of the preposition? (amount of xxxxx)

Thanks!
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Carcass,
"As" is not being used here as a comparison indicator. There are SIX uses for AS. Be careful.
A and B are wrong, in part, because satellites are countable, but "amount" is for uncountable stuff.

Do your nickname refer to the metal band Carcass ?
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A. as the amount of both space debris and satellites...... : Amt of Satellites = Eliminated

B. ...........the amount of satellites and space debris : Amt of Satellites = Eliminated

D. with the continually increasing amount of space debris and the number of satellites : lets split the individual sections with the AND

with the continually inc amt of debris.........AND........with the continually increasing THE number of satellites = Does it not sound weird? Eliminated

E. the amount of space debris continuing to increase along with the number of satellites

Implies : The chances of collision increase WITH..... With what? The ans to this ? as stated in B

the amt of debris continuing to increase along with the no of satellites...... Along with WHAT of the no of satellites ?

Is it : the amt of debris continuing to increase along with the inc in no of satellites

OR

is it : the amt of debris continuing to increase along with the no of satellites continuing to increase

in both cases does it fall under the ambit of a sound construction/ does it make any structural sense : Eliminated

Left with C

C : as the amount of space debris and the number of satellites continue to rise

...........AS ( The amount of debris &The no of satellites ).......CONTINUE

............AS ( X & Y )........CONTINUE

.............AS ( X & Y BOTH= PLURAL )...........CONTINUE (PLURAL)

Leading to OA C, my understanding

Nothing wrong with D and E in "with" but I think both option D and E are too wordy. If you have a better concise option choose that. So eliminate D and E and choose C.
BTW my choice of DC and other eliminations was based on countable and non-countable quantities. debris in non-countable so amount of is fine but satellites is countable so amount of is not correct. It should have number of next to it. SO eliminated A, B