A ball of mass $1 \mathrm{~kg}$ hangs in equilibrium from two strings $O A$ and $O B$ as shown in figure. What are the tensions in strings $O A$ and $O B ?$ (Take $g=10 \mathrm{~ms}^{-2}$ )
(a) $5 \mathrm{~N}$, zero
(b) Zero, $\mathrm{N}$
(c) $5 \mathrm{~N}, 5 \sqrt{3} \mathrm{~N}$
(d) $5 \sqrt{3} \mathrm{~N}, 5 \mathrm{~N}$