1) Is 2-methyl-2-propanamine (C4H11N) a primary amine, secondary amine, tertiary amine, or quaternary ammonium salt? 2) Is N-methyl-2-propanamine a primary amine, secondary amine, tertiary amine, or quaternary ammonium salt? 3) Is 3-ethyl-N-methylcyclohexanamine a primary amine, secondary amine, tertiary amine, or quaternary ammonium salt?