Tertiary amines may be obtained by:

Primary amines may be obtained by:

Primary, secondary and tertiary amines may be separated by using

Due to steric effect tertiary amines may not be more basic than secondary amines

The nitrogan atom in each of the following tertiary amines may be removed as trimethyl amine by repeated Hoffmann elimination. Which of the following amines requires the greater number of Hofmann sequence to accomplish this?