Answer:
C. [tex]2x+2y=8[/tex]
Step-by-step explanation:
We have been given equation of line A as [tex]x+y=4[/tex]. We are asked to choose the equation line B from our given choices, so that set of equations has infinitely many solutions.
We know that a set of equations has infinitely many solutions, when they represent same line or they are coincident.
Upon looking at our given choices, we can see that option C is the correct choice as we will get same line, when we will divide equation by 2 as:
[tex]2x+2y=8[/tex]
[tex]\frac{2x}{2}+\frac{2y}{2}=\frac{8}{2}[/tex]
[tex]x+y=4[/tex]
Therefore, option C is the correct choice.