Which of the following topological spaces is/are connected?\\
(A) $\mathrm{GL}_{1}(\mathbb{R})$\\
(B) $\mathrm{GL}_{1}(\mathbb{C})$\\
(C) $\mathrm{GL}_{2}(\mathbb{R})$\\
(D) $\left\{\left[\begin{array}{cc}x & -y \\ y & x\end{array}\right] : x, y \in \mathbb{R}, x^{2}+y^{2}=1\right\}$