Answer:
D. The lines coincide.
Step-by-step explanation:
Since, a system of two lines
and
,
Has a point of intersection, if,

Has infinitely many solution ( i.e. lines are coinciding ), if,

Has no solution ( i.e. lines are parallel ), if,

Here, the given system of equations,
y = 4 - x ⇒ x + y = 4,
2y = 8 - 2x ⇒ 2x + 2y = 8

Thus, by the above explanation,
The given lines coincide.
Option 'D' is correct.