Step 1: Concept
At equilibrium, the vertical components of tension balance the weight ($2T \cos\theta = mg$).
Step 2: Meaning
$\theta = 30^{\circ}$, $m = 10\sqrt{3}$ kg, and $g \approx 9.8~ms^{-2}$.
Step 3: Analysis
$2T \cos 30^{\circ} = 10\sqrt{3} \times 9.8$.
$2T (\frac{\sqrt{3}}{2}) = 10\sqrt{3} \times 9.8 \implies T\sqrt{3} = 98\sqrt{3}$.
Step 4: Conclusion
$T = 98 \text{ N}$.
Final Answer: (C)