For the given vectors \(\overrightarrow{a}=2i-j+2k\) and \(\overrightarrow{b}=-i+j-k\)

I: Sum of the two vectors is i + j + k

II: If \(\overrightarrow{c}=\overrightarrow{a}+\overrightarrow{b}\), then \(\mid \overrightarrow{c}\mid \) = √2 

III: Unit vector in the direction of  is \(\overrightarrow{a}+\overrightarrow{b}\) is \(\frac{i}{\sqrt 2 }+\frac{k}{\sqrt 2 }\)

Which of the following statement(s) is/are correct?