Correct answer is : 62
Let M\((3\lambda + 1,\ 2\lambda,\ 4\lambda + 2)\)
\(\overrightarrow{\mathrm{AM}} \cdot \overrightarrow{\mathrm{b}}=0\)
\(\Rightarrow \quad 9 \lambda-15+4 \lambda-2+16 \lambda-12=0\)
\(\Rightarrow \quad 29 \lambda=29\)
\(\Rightarrow \quad \lambda=1\)
\(\mathrm{M}(4,2,6), \mathrm{I}=(2,3,7)\)
Required Distance \(=\sqrt{4+9+49}=\sqrt{62}\)