Which from following statements is NOT correct?

A compound made of elements $$\mathrm{A}$$ and $$\mathrm{B}$$ form fcc structure. Atoms of A are at the corners and atoms of B are present at the centres of faces of cube. What is the formula of the compound?

What are different possible oxidation states exhibited by scandium?

Which from following is the slope of the graph of rate versus concentration of the reactant for first order reaction?