Database-Management-System

Consider the following implications relating to functional and multivalued dependencies given below, which may or may not be correct.
(i) If A ↠ B and A ↠ C then A → BC
(ii) If A → B and A → C then A ↠ BC
(iii) If A ↠ BC and A → B then A → C
(iv) If A → BC and A → B then A ↠ C
Exactly how many of the above implications are valid?