C0NSlDER A RELATl0N R WlTH ATTRlBUTES ABCDEF. Y0U ARE GlVEN THE F0LL0WING DEPENDENClES A > C, D > E, BC > D.

1) ATTRlBUTE CL0SURE 0F A?

2) ATTRlBUTE CL0SURE 0F B?

3) ATTRlBUTE CL0SURE 0F BC?

4) ATTRlBUTE CL0SURE 0F AB?

5) ATTRlBUTE CL0SURE 0F DF?

6) lDENTlFY WHlCH, lF ANY, 0F THE AB0VE ARE CANDlDATE KEYS.