Correct option is : (1) 3
\(\frac{x-1}{2-1}=\frac{y-2}{3-2}=\frac{z-3}{5-3}\)
\(\Rightarrow \frac{x-1}{1}=\frac{y-2}{1}=\frac{z-3}{2}=\lambda\)

\(\mathrm{B}(1+\lambda, 2+\lambda, 3+2 \lambda)\)
D.R. of \(\mathrm{AB}=<\frac{3 \lambda-8}{3}, \frac{3 \lambda-5}{3}, \frac{6 \lambda-10}{3}>\)
В \(\left(\frac{5}{3}, \frac{8}{3}, \frac{13}{3}\right) \frac{3 \lambda-8}{3 \lambda-5}=\frac{2}{1} \Rightarrow 3 \lambda-8=6 \lambda-10\)
\(3 \lambda=2\)
\(\lambda=\frac{2}{3}\)
\(\mathrm{AB}=\frac{\sqrt{36+9+36}}{3}=\frac{9}{3}=3\)