If the sum of two prime numbers is $$39$$, the difference between these two prime numbers will be ． 
Overseas Competition->Knowledge Point->Number Theory Modules
Because $$39$$ is an odd number, one of the two numbers must be an even prime number $$2$$. The other number is $$39-2=37$$, and their difference is $$35$$.  So the answer is $$\text{B}$$. 