you've actually pointed out the error yourself!

remember that you have to read extremely literally.

if you read this choice extremely literally, it says that households have grandparents (i.e., the households THEMSELVES - not the people in them - have grandparents).
this is absurd.

--

note that you must ALWAYS read with an extremely literal bent.
this will preclude many expressions that are commonplace in spoken language. for instance, it's incorrect to write that "an author was published twice in the last year", because authors themselves are not published. (you would have to say that the author's work was published twice in the last year.)

I have an idea an wish Ron, Manhantan Experts, and members to comment.

Questioning the OA.

In the past, I sometimes made mistake, questioning the OA.

Why do I do so?

we have tendency to look for error in a choice without comaring the choice with another choice.

gmat test us not only ABSOLUTE ERROR, but also, RELATIVE ERROR.

the words I devise.

absolute error is basic grammar errors. "he am" is wrong, absolute error.

relative errors are errors which appear when 2 choices are compared . For example.

"to do" is right when compared with "for doing" in another choice.

but

"for doing" can be in OA in another SC problem. Ron used to said this thing. "for doing" appear in OA in paralell forms.

The main point is that we look for both 2 types of error and the OA is not absolutely correct. the OA is best.

I get into habit of looking error from comparion and reading the entire original sentence before comparing choices. I feel better. /

This way of thinking is good for SC.

Is my thinking correct?

hi --
there are a lot of thoughts in that post; i can't tell exactly what your question is.
could you please state your question in a single sentence?

thanks.