Regarding the Interchangeability of Subqueries and Joins

Multiple Choice

Regarding the interchangeability of subqueries and joins,

A) a join can always be used as an alternative to a subquery,and a subquery can always be used as an alternative to a join.
B) a join can sometimes be used as an alternative to a subquery,and a subquery can sometimes be used as an alternative to a join.
C) a join can always be used as an alternative to a subquery,and a subquery can sometimes be used as an alternative to a join.
D) a join can sometimes be used as an alternative to a subquery,and a subquery can always be used as an alternative to a join.
E) a join can never be used as an alternative to a subquery,and a subquery can never be used as an alternative to a join.