An entity sold a depreciable asset in the middle of the fifth year of its estimated $10-$year useful life. The original cost of the asset was R$100000,$ and it was being depreciated on the straight$-$line basis. If the asset was sold for R$80000,$ the gain on the sale will be

A$.$ R$20000$

B$.$ R$25000$

C$.R30000$

D$.$ R$35000$