Someone pls help me with this it’s due in 10 min pls

The answer for #3 is c but i don't know why

Write a paragraph that provides examples of each stage of volcanic activity, a description of the volcano, and facts about each stage.

Consider the reaction: n2(g) + o2(g) ? 2no(g) kc = 0.10 at 2000oc starting with initial concentrations of 0.040 mol/l of n2 and 0.040 mol/l of o2, calculate the equilibrium concentration of no in mol/l how would this be done?