A line is passing through $(\alpha, \beta, \gamma)$ and its direction cosines are $l, m, n$ then the equations of the line are- (a) $\frac{x}{l}=\frac{y}{m}=\frac{z}{n}$ (b) $\frac{x-\alpha}{l}=\frac{y-\beta}{m}=\frac{z-\gamma}{n}$ (c) $\frac{x+\alpha}{l}=\frac{y+\beta}{m}=\frac{z+\gamma}{n}$ (d) $\frac{x-\alpha}{l}=\frac{y+\beta}{m}=\frac{z-\gamma}{n}$