Mary wanted to buy $12$ lemons. The lemons were sold either for $90$ cents each or at $3$ dollars for a bag of $4$ lemons. How much money would Mary save if she buys three bags of lemons instead of buying $12$ lemons separately? 
选项为:A:$1.2$ dollars  B:$1.5$ dollars  C:$1.6$ dollars  D:$1.8$ dollars  E:$2.1$ dollars  请回答其中一个选项.