Find the Missing Skeleton.

There are 2 of each shape. The missing ones are all present in only choice D.

There also exists a numeric solution. Treat each size of circle as a different number (smallest being 1, then 2, and finally 3 for the largest). Then treat each filled in circle as the additive inverse (so the smallest circle colored in will be -1). You can then assign a value to each slot by adding the two circles (so the top left corner would be 1, the slot to the right would be 2, etc.). When you add up all slot values of each row and column individually (that are currently completed), you get either 8 or 11. The only choice that makes every row and column in the grid add up individually to 8 or 11 is choice D.

no 2 dark - circle - within - a - big - circle are together side by side..putting A/B/C, the pieces will be together..so, my option was D

On the upper part. the square containing the black circles are on this pattern (/) including the circle with smaller circle inside. So i'm thinking that on the lower part , the pattern will be ( \ ) this one. and the one satisfying my guess is letter D. \m/