Given, \( \mathbf{a}+\mathbf{b}+\mathbf{c}+\mathbf{d}=0 \), which of the following statements ar...

Given, \( \mathbf{a}+\mathbf{b}+\mathbf{c}+\mathbf{d}=0 \), which of the following statements are incorrect?
(a) \( \mathbf{a}, \mathbf{b}, \mathbf{c} \) and \( \mathbf{d} \) must each be a null vector.
(b) The magnitude of \( (\mathbf{a}+\mathbf{c}) \) equals the magnitude of \( (\mathbf{b}+\mathbf{d}) \)
(c) The magnitude of a can never be greater than the sum of the magnitudes of \( \mathbf{b}, \mathbf{c} \) and \( \mathbf{d} \).
(d) \( \mathbf{b}+\mathbf{c} \) must lie in the plane of \( \mathbf{a} \) and \( \mathbf{d} \), if \( \mathbf{a} \) and \( \mathbf{d} \) are not collinear and in the line of \( \mathbf{a} \) and \( \mathbf{d} \), if they are collinear.