We have :

\(\left(x-2\right)^2\ge0\)

=> \(\left(x-2\right)^2+10+5+3\ge18\)

So \(B\) reach the smallest value equal 18 when the :

\(\left(x-2\right)^2=0< =>x-2=0=>x=2\)

We have : 

\(\left(x-2\right)^2\ge0\)

=> \(\left(x-2\right)^2+5+10+3\ge18\)

So \(x\) reach the smallest value equal 18 when the :

\(\left(x-2\right)^2=0< =>x-2=0=>x=2\)