_)I had not believed in falling in love with somebody at first sight_______I met David on Valentine’s Day three years ago.

A.when                 B.unless                       C.if                       D.before

I had not believed in falling in love with somebody at first sight_______I met David on Valentine’s Day three years ago

1. A.
   when
2. B.
   unless
3. C.
   if
4. D.
   before