Which of the following statements are correct ?

Question

$\begin{array}{1 1}(a)\;\text{Formaldehyde does not form simple amine with }NH_3\text{but forms urotropine}\\(b)\;\text{ Toluene can be oxidised to bentaldehyde by using alkaline }KMnO_4\\(c)\;\text{Acetamide on heating with }P_2O_5\text{produces methanenitrile}\\(d)\;\text{None of these}\end{array}$