A block rests on a rough inclined plane making an angle of \( 30^{\circ} \) with horizontal. The...

A block rests on a rough inclined plane making an angle of \( 30^{\circ} \) with horizontal. The coefficient of static friction between the block and inclined plane is 0.8 . If the frictional force on the block is \( 10 \mathrm{~N} \), the mass of the block in \( \mathrm{kg} \) is \( \left(g=10 \mathrm{~m} / \mathrm{s}^{2}\right) \)
(a) 2.0
(b) 4.0
(c) 1.6
(d) 2.5