| $\vec A$ + $\vec B$ | = | $\vec A$ - $\vec B$ |
This will be true when either $\vec A$ or $\vec B$ is zero. Also when $\vec A$ and $\vec B$ are perpendicular.(α = 90⁰) ,
| $\vec A$ + $\vec B$ | = | $\vec A$ - $\vec B$ | = $\sqrt {{A^2} + {B^2}}$
So Option - (4) is right

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| +| = | -|This will be true when either or is zero. Also when and are perpendicular.(α = 900) ,|+| = | -| = So Option - (4) is right