Amine basicity is a question I see debated all the time. The answer is NOT so straightforward because it DEPENDS if you are in the gas phase or in aqueous solution. In the gas phase, hydrogen bonding plays no role, thus the factor is the degree of substitution. Tertiary amines are most basic, then secondary, then primary amines . In aqueous solution, we must concern ourselves with solvent effects. The SECONDARY amine would be most basic, followed by primary and tertiary amines being very nearly the same. If this does appear on the DAT exam.....assume gas phase unless it is stated as an aqueous solution. To read more details about what I said, I refer you to the text book written by Professor Emeritus of Princeton University, namely Maitland Jones, Jr.