This puzzle is said to be from a Russian test and has an obvious but not fully fitting answer:
The task is to find correct picture to replace question mark.
The "obvious" pattern is
that a small "snake" or 2 triangles goes down from top to bottom, from left to right. Then the answer is A.
But of course in this case the 5th picture must still have a triangle in the middle. That is one reason to dislike this answer; another would be that it doesn't explain why only 2 triangles move and the 3rd stays still.
I can't solve it. Maybe you can?
P.S. Word-by-word translation of the Russian text from the picture:
What from the following replaces question mark in the given sequence?