It is found that \( |\vec{A}+\vec{B}|=|\vec{A}| \). This necessarily implies (A) \( \vec{B}=0 \)...

It is found that \( |\vec{A}+\vec{B}|=|\vec{A}| \). This necessarily implies
(A) \( \vec{B}=0 \)
(B) \( \vec{A}, \vec{B} \) are antiparallel
(C) \( \vec{A}, \vec{B} \) are perpendicular
(D) \( \vec{A} \cdot \vec{B} \leq 0 \)