Correct Answer:

Solution : According to the question figure –
In the first and second figures, the outer shape goes into the inner one and also rotates 45°. Also, the blocks on the edges flip in the second figure.
Similarly, for the third and fourth figures, the outer shape (triangle) shifts inside the square and rotates 45°. The square becomes the outer shape and the blocks are also flipped.
So, the required missing figure is –

Hence, the third option is correct.