This kind of CD－ROM is very populr. Why not buy one before it________ comes outB．is come

This kind of CD－ROM is very populr. Why not buy one before it________ comes outB．is come out C．sThis kind of CD-ROM is very populr. Why not buy one before it________ comes out B．is come out C．sells out D．is sold outA．comes outB．is come outC．sells outD．is sold out