What is the difference between a candidate key and a primary key?

Question

Is it that a primary key is the selected candidate key chosen for a given table?

Answer 1

A table can have so many column which can uniquely identify a row. This columns are referred as candidate keys, but primary key should be one of them because one primary key is enough for a table. So selection of primary key is important among so many candidate key. Thats the main difference.