Given,
The half figure of the shape is shown in question tab.
Required
The remaining half part of the figure to complete the symmetry.
Symmetry is defined as the balanced and proportional similarity that is found in two halves of an object. The imaginary line or axis along which on folding a figure to obtain the symmetrical halves is called the line of symmetry.
From the diagram, it is seen that the remaining part of the figure is option d shape.
On joining both shapes it shows symmetry.
Hence, option d is correct.