Explanation

(c)
Equation of the straight lines are
$3x - 4y + 7 = 0$ …(i)
and $12x + 5y - 2 = 0$ …(ii)
The equation of bisectors of the angles between these lines are
$\frac{3x - 4y + 7}{\sqrt{3^{2} + 4^{2}}} = \frac{12x + 5y - 2}{\sqrt{12^{2} + 5^{2}}}$
$\Rightarrow \frac{3x - 4y + 7}{5} = \frac{12x + 5y - 2}{13}$
$\Rightarrow 39x - 52y + 91 = 60x + 25y - 10$
$\Rightarrow 21x + 77y - 101 = 0$