The IUPAC name for $\text{CH}_3 - \text{CH}_2 - \text{N}(\text{CH}_3) - \text{CH}_2 - \text{CH}_2 - \text{CH}_3$ is : (A) N-methylpentan-2-amine (B) N-ethyl-N-methylpropan-1-amine (C) N,N-diethylpropan-1-amine (D) N,N-dimethylpropan-1-amine