QUESTION $7$

If $f(x,y,z)=xy+yz+zx+1,$ then gradf$(1,1,1)=$

a$.($:$1,2,1$:$)$

b$.($:$0,1,2$:$)$

c$.($:$1,2,0$:$)$

d$.($:$2,2,2$:$)$

e$.($:$0,2,0$:$)$