Each cell has a blue bar and an orange bar. Compare the bars of the third cell in a row with the bars of the first two cells. Which cell is missing?

In every row each bar of the third cell is as tall as the matching bars of the first two cells stacked together (top row: blue $1+2=3$ units, orange $2+1=3$ units, counting the shortest bar as one unit). In the bottom row the blue bars are 3 and 2 units and the orange bars 1 and 4 units, so the answer has blue 5 and orange 5: (c). (a) and (d) add only one pair of bars correctly and (b) takes the bars away from each other.