Answer : The correct option is, 4.0 mole
Explanation : Given,
Moles of lithium = 12 mole
The given balanced chemical reaction is:

By the stoichiometry we can say that, 6 moles of Li react with 1 mole of
to give 2 moles of

As, 6 moles of lithium react to give 2 moles of lithium nitride
So, 12 moles of lithium react to give
moles of lithium nitride
Therefore, the number of moles of lithium nitride produced will be 4.0 mole.