Answer:
Thus, option (a), (b) , (c) , (d) are correct.
The system will have no solution for all values except 12.
Step-by-step explanation:
  Given a system of equation y = –2x + 4  and 6x + 3y = ?
We have to check for which value the '?'  would result in a system of equations with no solution.
Consider a system of equation  
For the system to have no solution the condition is,
 
For the given system of equation , 
Let unknown quantity be v.
 y = –2x + 4   ⇒ 2x +y - 4 = 0   
and 6x + 3y = v ⇒  6x + 3y - v =0 
On comparing, we get,

Substitute the values in condition for no solution , we get ,

Consider second and third ratio, we get,

Solve for v , we get,
 
  
Thus, for all values v except v = 12 
The system will have no solution 
at v = 12 the system will have infinite many solution.
Thus, option (a), (b) , (c) , (d) are correct.