The correct option is C y=2x−3
We have, 2x−y=4
y=2x−4
Slope =m=2
As parallel lines have equal slopes. Hence, the slope of line we need will have slope =2.
Assume, equation of line as y=2x+c.
Point (2,1) satisfies this equation, hence
1=2×2+c
⇒c=−3
The equation of line is
y=2x−3