Which element out of L, M, Q. R will most readily form a diatomic molecule ?

The electronic configuration of four atoms are given in brackets : L(1s^(2)2s^(2)2p^(1))," "M(1s^(2)2s^(2)2p^(5)), Q(1s^(2)2s^(2)2p^(6)3s^(1))," "R(1s^(2)2s^(2)2p^(2)), The element that would most readily form a diatomic molecule is

Which of the following forms a diatomic molecule?

Which element does not form stable diatomic molecules ?