Each row and each column of this grid follows the same rule. Which figure belongs in the centre cell?

Every row and every column contains a circle, a triangle and a square exactly once, and also 1, 2 and 3 dots exactly once. The middle row (and the middle column) already has a triangle and a circle, with 3 and 2 dots (2 and 3 dots in the column), so the centre needs a square with 1 dot: (a). (b) and (d) have the right shape but repeat a dot count, and (c) repeats the circle.