question_answer

Consider the relation \[R=\left\{ \left( a,b \right),\left( a,c \right),\left( a,a \right),\left( c,c \right) \right\}\]on the set \[A=\left\{ a,\text{ }b,\text{ }c,\text{ }d \right\}\]Minimum number of elements of A x A which must be adjoined to R in order to make R an equivalence relation is

A)  4  

B)                     5            

C)  6    

D)  7