The breadth of a rectangular bookmark is $9$ cm. It\textquotesingle s length is $3$ times its breadth. What is the area of the bookmark? 
选项为:A:27 cm\textsuperscript{2}  B:81 cm\textsuperscript{2}  C:162 cm\textsuperscript{2}  D:243 cm\textsuperscript{2}  请回答其中一个选项.