Correct Answer - A
In free state, all alkali metals exhibit ON zero but exhibit ON of `.+1` in their compounds on account of strong tendency to lose `ns^(1) e^(-)` because of low `Delta_(i)H_(1)`. They never exhibit `.+2` and higher oxidation numbers in their compounds as the loss of 2nd electron is quite difficult on account of every high `Delta_(i)H_(2)`.
