d
(d)From the property of vector product, we notice that \(\overrightarrow C \) must be perpendicular to the plane formed by vector \(\overrightarrow A \) and \(\overrightarrow B \). Thus \(\overrightarrow C \) is perpendicular to both \(\overrightarrow A \) and \(\overrightarrow B \) and \((\overrightarrow A + \overrightarrow B )\)vector also, must lie in the plane formed by vector \(\overrightarrow A \) and \(\overrightarrow B \). Thus \(\overrightarrow C \) must be perpendicular to \((\overrightarrow A + \overrightarrow B )\) also but the cross product \((\overrightarrow A \times \overrightarrow B )\) gives a vector \(\overrightarrow C \) which can not be perpendicular to itself. Thus the last statement is wrong.