Can any of you solve this puzzle?

[countdowntonap]

It’s driving me mad!

I think C. Working top row, left to right. The 2 white boxes are either side of the line and are the same quantity, so cancel each other out, leaving in the top right two black on the left of the line. On the middle row, left to right, everything is just on the right of the line, so add picture one to picture two and you end up with picture three. Bottom row from left, take away the white box on either side of the line and combine both images, to get picture C?

I agree with @QueenofDrudgery . If you combine the first and second pictures on each line, you get the third.

Basically, a box to the left of the line is +1 and a box to the right is -1.

exactly. C add what's on the same side, subtract what's on the opposite side.

Geniuses!! Thank you!

Also C - a bit like simplifying an equation