On a Hot Summer Day, Water Collects on the Outside

On a hot summer day, water collects on the outside of a glass of iced lemonade. The water comes from

A) inside the glass since glass is porous.
B) the condensation of the water vapor due the fact that the glass is much colder than the air.
C) the straw you use to drink your lemonade.
D) the mixture of water and lemonade.
E) It is one of the mysteries of life.