Correct Answer:

Solution : According to the question figure –
1. In the given series, the horizontal lines are increasing and the vertical lines are decreasing successively.
2. The geometrical shape changes between triangle and square while moving along the corners in a clockwise direction.
So, following the above pattern, the required figure will be as follows –

Therefore, the complete figure is as follows –

Therefore, the figure in the third option is the required figure. Hence, the third option is correct.