Answer:
x - y = 0
Explanation:
General form of equation of straight line is
ax + by = c
that is we have to keep terms containing x and y on LHS and term independent of x and y on RHS.
given
x = y
there, no term independent of x and y
now we have to bring y one RHS
for that we subtract y from LHS and RHS
x - y = y -y
=> x - y = 0
Thus, option x - y = 0 is the correct answer.