Let the equal intercepts on the axes be a. Equation of line in intercept form:

(x/a)+(y/a)=1 or x+y=a. As it passes through (-1,2) ; -1+2=a => a=1.

Required equation of line is x+y=1.

Alternatively, Since line passes through (-1,2), it should satisfy the equation of line. And in this cases putting the value, Only option (c) gives L.H.S=R.H.S.