In general, the most materially advanced and developed countries are focused on extensive development of the ___________ sector of their economy.

A. Secondary
B. Tertiary
C. Primary
D. Quaternary

I picked A, because the modern materially wealthy countries achieved their prominence from the secondary sector of production in manufacturing and construction.

Is this answer right or am I totally off base?

7 answers

I disagree.

http://geography.about.com/od/urbaneconomicgeography/a/sectorseconomy.htm
I read the document you left a link for and according to that it is Tertiary sector. Correct.
I think it's at least tertiary, but more likely quaternary.
It is not tertiary I fall the question buy puting that
I think C is correct
I think not...
It's E all of the above
the answer is A secondary just took test