The correct options are
A x+2y−π=0
B x+2y+π=0
Let (x1,y1) be the point of contact of one of the tangents.
Tangent is parallel to x+2y=0
Slope of the tangent is, m=−12
y=sin(x+y)
⇒dydx=−12
⇒cos(x+y)(1+dydx)=−12
At (x1,y1), we get
cos(x1+y1)(1−12)=−12
⇒cos(x1+y1)=−1⇒x1+y1=π,−π
So, y1=sin(x1+y1)=0
⇒x1=π,−π
Equations of tangents are
y−0=−12(x−π) and y−0=−12(x+π)
Hence, the required equation of the tangents are
x+2y−π=0 and x+2y+π=0