I think this may be a grammatically incorrect statement. The reason I say so is because "which" used a modifier always modifies the word immediated before it. In this case the word it modifies is "shows". This would require the modifier to state "which are" instead of "which is" because "shows" is plural.

Out of x grows y is a complete statement and not a preposition phrase. So interest can be the subject.

Here 'a growing market' is the subject and 'which is' correctly refers to 'a growing market'

You absolutely right about the subject. If I would have paid attention to my Out of x grows y formula, y is the subject. So in this case the growing market would be the subject, because your not talking about x growing out of something.

But, to quote my Manhattan GMAT SC guide, "Use WHICH only to refer to the noun immediately preceding it -- never to an entire clause." In this case the noun immediately preceding which is shows, not the entire clause "a booming market for "reality" television shows". Thus, they are either using which incorrectly or they incorrectly used is where they should have used are.

here2learn wrote:From Kaplan 800 guide:

Out of the public's interest in the details of and conflicts in other people's lives has grown a booming market for "reality" television shows, which is bringing "regular" people onto the tv screen with increasing frequency.

WHICH refers to "television shows"
VERB HAS is for subject "interest"

akhp77 wrote:

here2learn wrote:From Kaplan 800 guide:

Out of the public's interest in the details of and conflicts in other people's lives has grown a booming market for "reality" television shows, which is bringing "regular" people onto the tv screen with increasing frequency.

WHICH refers to "television shows"
VERB HAS is for subject "interest"

Please address my previous post if you say the subject is interest. I'd have to disagree and clearly so do the Kaplan people. Not to try to call you out, but to make sure that if I did make an error that I don't make it in the future.

By the way I believe the idiom is, Out of x has grown y, or Y has grown out of x. Either way the subject is y, not x. The difference only being the active or passive voice. Thus the subject in this instance would be a booming market, not interest.

Also symantics can be symantics, but the noun immediately preceding which would be shows whether there is a modifier (eg "television") or not.

Out of the public's interest in the details of and conflicts in other people's lives has grown a booming market for "reality" television shows, which is bringing "regular" people onto the tv screen with increasing frequency.

In KAPLAN 800, It is mentioned THAT not WHICH.
Sentence correction practice set 11 - Problem 27

Any way please the expert's explanation for better standing about above problem in below link.

https://www.beatthegmat.com/reality-tele ... 54890.html

Manhattan guide says that..a sentence can be inverted and verb can come before the subject...
That is the case here..
Lets simplify this sentence...
A booming market for reality shows out of public's interest in the details of and conflicts in other people's life, .............

This simplified sentence is same as what original is and the subject is clearly singular...A booming market...
HTH!!