We no longer keep up the close friendship we used to have years

We no longer keep up the close friendship we used to have years ago,（ ）we still visit each other occasionally.

since

though

because

for

前半句为“再也不能保持我们多年前亲密的友谊”，后半句为“我们偶尔也会相见”，前后为转折关系，选B。句意：我们再也不能保持我们多年前亲密的友谊，尽管我们偶尔也会相见。