Which of the following sentence is written correctly

A. add a little butter to the pan (you can use olive oil as a substitute, if you like

B . add a little butter to the pan {you can use olive oil as a substitute, if you like }

C . add a little butter to the pan--you can use olive oil as a substitute, if you like

D . add a little butter to the pan, you can use olive oil as a substitute, if you like