A block is kept on an inclined plane of inclination θ of length l. The velocity of particle at the bottom of inclined is (the coefficient of friction is μ)

(1) $\sqrt{2gl\left(\mu \mathrm{cos}\theta -\mathrm{sin}\theta \right)}$

(2) $\sqrt{2gl\left(\mathrm{sin}\theta -\mu \mathrm{cos}\theta \right)}$

(3) $\sqrt{2gl\left(\mathrm{sin}\theta +\mu \mathrm{cos}\theta \right)}$

(4) $\sqrt{2gl\left(\mathrm{cos}\theta +\mu \mathrm{sin}\theta \right)}$