On $1$ March $2017,$ Ronaldo Limited purchased a vehicle for R$625000$ and it was available for use as intended by management on $1$ April $2017.$ The vehicle has a current estimated residual value of R$35000.$ The vehicle is depreciated according to the production unit method. The estimated useful life of the vehicle is $125000$ km$.$ The vehicle travelled $40000$ km during the $2017$ financial year. Ronaldo Limited has a financial year$-$end of $31$ December.

How should Ronaldo Limited calculate the depreciation on this vehicle for the year ended $31$ December $2017?$

$($R$625000/125000$ km$)$ x $40000$ km x $10/12$

$($R$625000$ R$35000)/125000$ km x $40000$ km

$($R$625000/125000$ km$)$ x $40000$ km x $9/12$

$($R$625000/125000$ km$)$ x $40000$ km

None of the options

$($R$625000$ R$35000)/125000$ km x $40000$ km x $10/12$

$($R$625000$ R$35000)/125000$ km x $40000$ km x $9/12$