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**S**, **M**, **E** and **F** are working in shifts in a team to finish a project. **M** works with twice the efficiency of others but for half as many days as **E** worked. **S** and **M** have $6$ hour shifts in a day, whereas **E** and **F** have $12$ hours shifts. What is the ratio of contribution of **M** to contribution of **E** in the project?

- $1:1$
- $1:2$
- $1:4$
- $2:1$