Khẳng định nào sau đây Sai?

A.\[\mathop {\lim }\limits_{x \to + \infty } \frac{{{x^2} + 1}}{{2{x^2} + 1}} = \frac{1}{2}\]

B. \[\mathop {\lim }\limits_{x \to - \infty } \left( {{x^2} + 3x - 1} \right) = - \infty \]

C. \[\mathop {\lim }\limits_{x \to + \infty } \frac{{x + 1}}{{2x + 1}} = \frac{1}{2}\]

D. \[\mathop {\lim }\limits_{x \to - \infty } \frac{{x + 3}}{{2x + 1}} = \frac{1}{2}\]