Which of the following is true if consuming one unit of a good yields 100 utils and consuming the second unit of the good increases satisfaction by 20 utils? 
选项为:A:The marginal utility of the first unit is 20.  B:The marginal utility of the second unit is 20.  C:The marginal utility of the second unit is 120.  D:The total utility of consuming two units is 120.  E:The total utility of consuming one unit is greater than the total utility of consuming two units.  请回答其中一个选项.