Two plums and one cherry weigh $$80\text{g}$$. Two cherries and one plum weigh $$70\text{g}$$. What is the weight of four plums? 
选项为:A:$$30\text{g}$$  B:$$40\text{g}$$  C:$$50\text{g}$$  D:$$120\text{g}$$  E:$$160\text{g}$$  请回答其中一个选项.