Answer: D
\(\because\) AB\(^2\) = 2AC\(^2\)
Or, AB\(^2\) = AC\(^2\) + AC\(^2\)
Or, AB\(^2\) = BC\(^2\) + AC\(^2\) [\(\because\) AC = BC]
\(\therefore\) \( \triangle ABC \) is a right-angled isosceles triangle with AB as the hypotenuse.
Thus, the angle opposite to the hypotenuse AB, \(\angle C\), is a right angle, i.e., \(\angle C = 90^\circ\).
\(\because\) AB\(^2\) = 2AC\(^2\)
Or, AB\(^2\) = AC\(^2\) + AC\(^2\)
Or, AB\(^2\) = BC\(^2\) + AC\(^2\) [\(\because\) AC = BC]
\(\therefore\) \( \triangle ABC \) is a right-angled isosceles triangle with AB as the hypotenuse.
Thus, the angle opposite to the hypotenuse AB, \(\angle C\), is a right angle, i.e., \(\angle C = 90^\circ\).