In a parallelogram ABCD, if \[{{50}^{o}}\] \[{{60}^{o}}\] \[\angle BAD={{120}^{o}}\]and \[\angle BCD\] then ratio of AB: BC is

• A. 71:21             
• B. 0.507638888888889
• C. 31:35             
• D. 0.171527777777778