In \[\Delta ABC,\]If \[AB=BC\] and \[\angle B=40{}^\circ ,\]what is the measure of \[\angle C\]?

• A. \[70{}^\circ \]         
• B.  \[80{}^\circ \]           
• C.  \[130{}^\circ \]                        
• D.  \[40{}^\circ \]