Solution:

The main product is $C_6H_5CH_2OH$

When $C_6H_5CH_2NH_2$ reacts with HNO2, it produces an unstable diazonium salt, which is then converted to alcohol. When $C_6H_5CH_2NH_2$ reacts with HNO2, benzyl alcohol, as well as $N_2$ and $H_2O$, is formed. In this case, the chemical reaction at hand is

$C _{6} H _{5} CH _{2} NH _{2}+ HNO _{2} \longrightarrow C _{6} H _{5} CH _{2} OH + N _{2}+ H _{2} O$