Consider $\mathrm{Q}=\mathrm{ax}^{2}+\mathrm{bx}+\mathrm{c}$ where $\mathrm{a}, \mathrm{b}, \mathrm{c}$ are real and distinct. Also, $\mathrm{Q}=0$ has real roots Column 1 $\quad$ Column II
(a) If $\mathrm{a}, \mathrm{b}, \mathrm{c}$ are in $\mathrm{AP}$, then the least value of $\left|\frac{\mathrm{d}}{\mathrm{b}}\right|$ (where $\mathrm{d}$ is the common
(p) $-\sec ^{2} \frac{\pi}{4}$
difference), is
(b) If $\mathrm{a}, \mathrm{b}, \mathrm{c}$ are in $\mathrm{GP}$, then $\mathrm{b}$ cannot be equal to
(q) $\cos \frac{\pi}{3}$
(c) If $\mathrm{a}, \mathrm{b}, \mathrm{c}$ are in AP with common difference 'd', and if zero is a root of
(r) $\sin \frac{\pi}{3}$
$\mathrm{Q}=0$, then $\left|\frac{\mathrm{d}}{\mathrm{a}}\right|$ equals
(d) If $a, b, c$ are in $A P$, and $b, c$, a are in GP, then the common ratio $r$ equals
(s) $\sin \frac{\pi}{2}$