These die faces follow a pattern. Look at them in pairs. Which face comes next?

Taken in pairs, the faces add up to 7: 6 and 1, 5 and 2, so the 4 must be followed by $7-4=3$. (The first face of each pair also goes down by one: 6, 5, 4.) The answer is 3 dots: (d). (a) repeats the 4, (b) continues 1, 2 wrongly and (c) has only 1 dot.