Three workers $\text{A, B,}$ and $\text{C}$ complete a piece of work in $6$ days for which they are paid a sum of $\text{Rs. 1920.}$ If the efficiency of $\text{A, B,}$ and $\text{C}$ are in ratio $4:5:7,$ then find the daily income of $\text{C}$ ?
- $\text{Rs. 840}$
- $\text{Rs. 98}$
- $\text{Rs. 140}$
- $\text{Rs. 56}$