Let 3 a = 3 26 + 3 7 + 3 63 then

Answer: Option A

$$\begin{array}{rl}& \text{root}3\text{of}a=\text{root}3\text{of}26+\text{root}3\text{of}7+\text{root}3\text{of}63\\ & \text{Take round figure}\\ & \Rightarrow \text{root}3\text{of}a<\text{root}3\text{of}27+\text{root}3\text{of}8+\text{root}3\text{of}64\\ & \Rightarrow \text{root}3\text{of}a<3+2+4\\ & \Rightarrow \text{root}3\text{of}a<9\\ & \Rightarrow a<9^3\\ & \Rightarrow a<729\\ & \text{Option A is answer}\end{array}$$