Critical Reasoning

Besides laying eggs in her own nest, any female wood
duck will lay an egg in the nest of another female wood
duck if she sees the other duck leaving her nest. Under
natural nesting conditions, this parasitic behavior is
relatively rare because the ducks' nests are well hidden.
However, when people put up nesting boxes to help the
ducks breed, they actually undercut the ducks'
reproductive efforts. These nesting boxes become so
crowded with extra eggs that few, if any, of the eggs in
those boxes hatch.
The statements above, if true, most strongly support
which one of the following?
(A) Female wood ducks will establish nests in nest
boxes only when natural nesting sites are not
available.
(B) Nesting female wood ducks who often see other
female wood ducks are the most successful in
their breeding efforts.
(C) The nesting boxes for wood ducks have less space
for eggs than do natural nesting sites.
(D) The nesting boxes would be more effective in
helping wood ducks breed if they were less
visible to other wood ducks than they currently
are.
(E) Nesting boxes are needed to supplement the
natural nesting sites of wood ducks because of
the destruction of much of the ducks' habitat.

[spoiler]OA D. But I don't know why C is wrong.[/spoiler]

D is correct

first thing first in gmat solving CR we have got tremondous rule , its a must be true type of q and in this type of q one basic rule is to select an answer which is supported by the stimulus.
any answer which can be true or more likely be true but is not supported by the stimulus is always wrong.

in this C is tempting one but it requires us to assume that nesting boxes are smaller in size then natural nesting's size . noe the size of the nesting is not at all mentioned .

but D is correct bcoz ....a problem in breeding eggs in nesting boxes is discussed and a case of breeding of wood ducks is discussed . these two things are enough to answer the question
Hope i was able to clear the doubt

umaa wrote:Besides laying eggs in her own nest, any female wood
duck will lay an egg in the nest of another female wood
duck if she sees the other duck leaving her nest. Under
natural nesting conditions, this parasitic behavior is
relatively rare because the ducks' nests are well hidden.
However, when people put up nesting boxes to help the
ducks breed, they actually undercut the ducks'
reproductive efforts. These nesting boxes become so
crowded with extra eggs that few, if any, of the eggs in
those boxes hatch.
The statements above, if true, most strongly support
which one of the following?
(A) Female wood ducks will establish nests in nest
boxes only when natural nesting sites are not
available.
(B) Nesting female wood ducks who often see other
female wood ducks are the most successful in
their breeding efforts.
(C) The nesting boxes for wood ducks have less space
for eggs than do natural nesting sites.
(D) The nesting boxes would be more effective in
helping wood ducks breed if they were less
visible to other wood ducks than they currently
are.(E) Nesting boxes are needed to supplement the
natural nesting sites of wood ducks because of
the destruction of much of the ducks' habitat.

[spoiler]OA D. But I don't know why C is wrong.[/spoiler]

These days I Have developed a stratergy for myself to identify the "Keywords" which has some relation wrt to the answer to be identified.(look for the key words in the bold")

But I make sure,if an option exists then go for it when I am in dilema of picking the right one as in this case.

imo D

But I don't know why C is wrong

The nesting boxes for wood ducks have less space
for eggs than do natural nesting sites.


We cannot say C must be true based on what's given(without making extra assumptions) since:

The nesting boxes are visible to female ducks more so than the natural nesting created by the individual female ducks. All we know is that nesting boxes get crowded due to the reason mentioned abobe but there is no way to say if it is more spacious or less spacious than the nataural nesting places from just what's given in the argument.

Hence choose D Hope this helps.

Regards,
Cramya