Multiple choice

Determine the condition that the equation $\displaystyle z^{2}+\left ( p+iq \right )z+r+is= 0$ has real roots only.

$\displaystyle s^{2}+pqs+rq^{2}= 0$
$\displaystyle s^{2}+pqs+r^{2}= 0$
$\displaystyle s^{2}-pqs+rq^{2}= 0$
$\displaystyle s^{2}-pqs+r^{2}= 0$

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