Step 1 :The given equation is \(6x + 4 = 3x + 4\).
Step 2 :Subtract \(3x\) from both sides of the equation to get \(3x + 4 = 4\).
Step 3 :Subtract \(4\) from both sides to get \(3x = 0\).
Step 4 :Divide both sides by \(3\) to get \(x = 0\).
Step 5 :The solution to the equation is \(x = 0\). This means that the equation is a conditional equation, because it is only true for \(x = 0\).
Step 6 :Final Answer: \(\boxed{A. \{0\}}\)