Two plane mirrors are inclined at $90^{\circ}$. An object is placed between them whose coordinates are $(a, b)$. Find the position vectors of all the images formed : (Take $\ddot{\mathbf{i}}, \overrightarrow{\mathbf{j}}$ are unit vectors along $x-y$ axis)
(a) $-a \hat{\mathbf{i}}-b \hat{\mathbf{j}}, a \hat{\mathbf{i}}-b \hat{\mathbf{j}},-a \hat{\mathbf{i}}+b \hat{\mathbf{j}}$(b) $-a \hat{\mathbf{i}}+b \hat{\mathbf{j}},-a \hat{\mathbf{i}}-b \hat{\mathbf{j}}, a \hat{\mathbf{i}}-b \hat{\mathbf{j}}$
(c) $a \hat{\mathbf{i}}+b \hat{\mathbf{j}},-a \hat{\mathbf{i}}-b \hat{\mathbf{j}},+a \hat{\mathbf{i}}-b \hat{\mathbf{j}}$
(d) none of the above