Critical Reasoning

Spectroscopic analysis has revealed the existence of frozen nitrogen, methane, and carbon monoxide on the surface of Pluto. Such ices have a tendency to vaporize, producing an atmosphere. Since the proportion of any gas in such an atmosphere depends directly on how readily the corresponding ice vaporizes, astronomers have concluded that the components of Pluto's atmosphere are nitrogen, carbon monoxide, and methane, in order of decreasing abundance.
The astronomers' argument relies on which one of the following assumptions?
(A) There is no more frozen nitrogen on the surface of Pluto than there is either frozen carbon monoxide or methane.
(B) Until space probes reach Pluto, direct analysis of the atmosphere is impossible.
(C) There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide.
(D) Nitrogen is found in the atmosphere of a planet only if nitrogen ice is found on the surface of that planet.
(E) A mixture of nitrogen, carbon monoxide, and methane is characteristic of the substances from which the Solar System formed.

IMO C

Yeah u r correct.

Vineet try solving that Fastfood CR.Its interesting...

OA :C

Why not D

C might not be the strongest choice because there might be elements that are not detected by the spectro... analysis

What's the difference between answer choice A and C?

karthikpandian19 wrote:What's the difference between answer choice A and C?

Karthik,

A refers to the proportion of nitrogen, carbon monoxide and methane whereas C refers back to how readily it vaporizes - as described in the argument. The components of gases in the atmosphere are dependent on how readily the ice vaporizes and not on how much each component ice is present.

Regards
Anup

exactly . never in the premise they have mentioned about "Quantity of the gas"

in fact, a) is incorrect as it is contradicted by the argument. for nitrogen to be most abundant, % of nitrogen must be greater than % of either methane/carbon