Tìm điều kiện của x để biểu thức sau có nghĩa:a) \(\sqrt {2 - 5x} \)                  b) \(\frac{1}{{\sqrt {1 - x} }}\)                        c) \(\sqrt {{x^2} - 4x + 4} \)       ...

A \(\begin{array}{l}
a)\,\,x \le \frac{2}{5} & & b)\,\,x < 1\\
c)\,\,\forall x & & & d)\,\,x \ge 2
\end{array}\)

B \(\begin{array}{l}
a)\,\,x \le \frac{2}{5} & & b)\,\,x < 1\\
c)\,\,\forall x & & & d)\,\,x \le 2
\end{array}\)

C \(\begin{array}{l}
a)\,\,x \ge \frac{2}{5} & & b)\,\,x < 1\\
c)\,\,\forall x & & & d)\,\,x \ne 2
\end{array}\)

D \(\begin{array}{l}
a)\,\,x \le \frac{2}{5} & & b)\,\,x < 1\\
c)\,\,\forall x & & & d)\,\,x \ne 2
\end{array}\)