The Compound RX₃ Decomposes According to the Equation 3RX₃ →

The compound RX₃ decomposes according to the equation 3RX₃ → R + R₂X₃ + 3X₂
In an experiment the following data were collected for the decomposition at 100°C. What is the average rate at which RX₃ is disappearing over the entire experiment?

A) 0.011 mol L ⁻¹s ⁻¹
B) 0.019 mol L ⁻¹s ⁻¹
C) 0.044 mol L ⁻¹s ⁻¹
D) 0.049 mol L ⁻¹s ⁻¹
E) 0.069 mol L ⁻¹s ⁻¹