Please help!

Which statement is NOT correct?

a) In an ionic compound, a metal and a non metal form a compound, and electrons are transferred from one to the other.

b) In an ionic compound, a metal and a polyatomic ion form a compound, and electrons are shared.

c) In both ionic and molecular compounds, valence electrons take part in bonding.

d) In a molecular compound, a non-metal and a non-metal form a compound, and electrons are shared