We cannot completely avoid stress in our lives. We need to find ways to cope with it.  

A As long as we can completely avoid stress in our lives, we need to find ways to cope with it.

B Since we cannot completely avoid stress in our lives, we need to find ways to cope with it.

C Because stress can completely be avoided in our lives, we need to find ways to cope with it.

D After we can completely avoid stress in our lives, we need to find ways to cope with it.