若 $\sin ^2 x>\cos ^2 x$, 则 $x$ 的取值范围是
A
$\left\{x \left\lvert\, 2 k \pi-\frac{3}{4} \pi < x < 2 k \pi+\frac{1}{4} \pi\right., k \in \mathbf{Z}\right\}$
B
$\left\{x \left\lvert\, 2 k \pi+\frac{1}{4} \pi < x < 2 k \pi+\frac{5}{4} \pi\right., k \in \mathbf{Z}\right\}$
C
$\left\{x \left\lvert\, k \pi-\frac{1}{4} \pi < x < k \pi+\frac{1}{4} \pi\right., k \in \mathbf{Z}\right\}$
D
$\left\{x \left\lvert\, k \pi+\frac{1}{4} \pi < x < k \pi+\frac{3}{4} \pi\right., k \in \mathbf{Z}\right\}$
E
F