Taking stability as the factor, which one of the following represent the correct relationship?

Due to the inert pair effect, +1 state stability increases down the group and +3 state stability decreases down the group. Hence, ${\mathrm{Tl}}^{+}$ is more stable than ${\mathrm{Tl}}^{3+}$. Hence, $\mathrm{TlI}$ is more stable than ${\mathrm{TlI}}_3$.