Finally got it! The answer is
C
Reason
Each of four outer squares of the middle tile represent the halves of the adjacent tiles like so. The purple lines indicate which ‘half‘ each square is connected to…
The idea is to then add the number of dots in the halves that have been represented by the BIG purple dots and then take away the number of dots in the halves represented by the BIG clear dot(s) added together.
The resulting number of purple dots is then represented here:
So in the top row we have (2+2+3)-4=3 and so three dots in the center.
In the bottom row we have (6+4)-(7+1)=2 and so two dots in the center.
Therefore the middle row has the sum of the halves represented by the BIG purple dots (2+3)-(4) to make 1 dot in the center and the sum of the two halves represented by the BIG clear dots is therefore 4 making C the only option.