QUESTION $2$

If $(a,b)$ is the only critical point of $f(x,y)=x^2+xy+\frac{1}{2}{y}^2-2x+y,$ then

a$.a+b=1$

b$.f$ has a saddle point at $(a,b)$

c$.f$ has a relative minimum at $(a,b)$

d$.f$ has a relative maximum at $(a,b)$

e$.f(a,b)=5$