Find the complement of F (a, b, c, d) using Demorgan's Laws. Show the relevant reasoning.
F(a, b, c, d)=a + {(b + c).(b' + d')}

  [a + {(b + c).(b' + d')}]'
= a'.[{(b + c).(b' + d')}]'   [De-Morgan's Law]
= a'.{(b + c)' + (b' + d')'}  [De-Morgan's Law]
= a'.{(b'c') + (b''.d'')}     [De-Morgan's Law]
= a'.{(b'c') + (bd)}          [Involution Law: a''=a]
= a'b'c' + a'bd