Help on a Progressive Matrices test question

I need help with a specific question on an IQ test.

Go here

http://www.iqtest.dk/main.swf

And then goto question #39.

Someone linked me to this specific question on a chat room, but I could not figure out any pattern or strategy to pick the correct answer. Later, I decided to brute force the correct answer. I answered the first few questions correctly, then guessed on #39 until my score changed.

The answer is B.

I tried googling for any help to this question. Turns out lots of people are frustrated with this particular question.

Is there anyone that can figure out the reasoning for “B” being the correct answer? Any help would be appreciated.

P.S. Hopefully this is posted in the correct section of these forums.

Hint 1:As with many clues in this test, there is a logical progression from left to right on each row of the 3x3 grid.Hint 2:Try replacing Xs with Os, Os with triangles, and triangles with Xs as you go left to right.

And maybe one more hint:Look at the progression in question #19 as well.

Thanks for the hints but the first and second one are basically known intuitively when you start on the problem. I tried looking at #19 but it was simple compared to #39. I wasnt able to see any relationship between #19 and #39.

Do you know the logic behind the answer to #39? Would really appreciate it if you could just explain it thoroughly.

The symbols in each grid move left to right and loop around to the next row as in #19. After they move, they are substituted Xs with Os, Os with triangles, and triangles with Xs.