Question:
If $\left(a_{1}, b_{1}, c_{1}\right)$ and $\left(a_{2}, b_{2}, c_{2}\right)$ be the direction ratios of two parallel lines then
A. $\mathrm{a}_{1}=\mathrm{a}_{2}, \mathrm{~b}_{1}=\mathrm{b}_{2}, \mathrm{c}_{1}=\mathrm{c}_{2}$
B. $\frac{\mathrm{a}_{1}}{\mathrm{a}_{2}}=\frac{\mathrm{b}_{1}}{\mathrm{~b}_{2}}=\frac{\mathrm{c}_{1}}{\mathrm{c}_{2}}$
C. $a_{1}^{2}+b_{1}^{2}+c_{1}^{2}=a_{2}^{2}+b_{2}^{2}+c_{2}^{2}$
D. $a_{1} a_{2}+b_{1} b_{2}+c_{1} c_{2}=0$
Solution:
