The stability of `+1` oxidation state increases in the sequence :

Options

A. `Al lt Ga lt In lt Tl`
B. `Tl lt In lt Ga lt al`
C. `In lt Tl lt Ga lt Al`
D. `Ga lt In lt Al lt Tl`

Answer

A

Explanation

Due to inert pair effect the stability of lower oxidation state increases down the group