Count the dots in every cell. How is the last cell of each row related to the first two? Choose the missing figure.

In every row the dots in the third cell are the sum of the dots in the first two: $1+2=3,2+2=4$. The bottom row needs $3+1=4$ dots inside a square: (d). (a) copies the first cell, (b) has 5 dots and (c) uses the wrong shape.