Simon cut a cake into $$12$$ equal pieces. He ate $3$ pieces and both his parents ate $$2$$ pieces each. What fraction of the cake was left？ 
选项为:A:$$\dfrac{3}{12}$$  B:$$\dfrac{4}{12}$$  C:$$\dfrac{5}{12}$$  D:$$\dfrac{7}{12}$$  请回答其中一个选项.