How many pairs of co-primes can be formed from the set \[\left\{ 2,\text{ }5,\text{ }6,\text{ }7,\text{ }8,\text{ }9,\text{ }12 \right\}\]

• A.  14                   
• B.         13        
• C.  12                   
• D.         18
• E.  None of these