Given the Following Amines

Given the following amines:
These three amines all have the same formula weight. Rank them in order of increasing boiling point. (From lowest to highest.)

A) 1^º < 2^º < 3^º
B) 2^º < 1^º < 3^º
C) 3^º < 2^º < 1^º
D) 3^º < 1^º < 2^º