Answer:
C
Step-by-step explanation:
The equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
Given
y - x = 5 ( add x to both sides )
y = x + 5 ← in slope- intercept form
with slope m = 1
Parallel lines have equal slope, thus
the slope of a parallel line is m = 1 → C