Which answer figure will complete the pattern in the question figure 

The pattern followed is that the diagonal figures are opposite of each other, in the right diagonal the triangles are pointed inside and then outside respectively.

Similarly, in the missing figure, there will be a circular portion, and thus the last two options are eliminated.

Also, lower right side of the square is missing, and the second figure is not practical with the missing portion, thus it is also eliminated.

=> Ans - (A)