Why Canʹt Plants Use N2 Directly as a Nutrient

Why canʹt plants use N2 directly as a nutrient?

A) N2 diffuses out of leaves as quickly as it diffuses in, so it has to be ʺfixedʺ to remain in leaves.
B) Plants lack the enzymes necessary to convert N2 into NO3−or NH4+.
C) Most soils are depleted of N2 as a nutrient.
D) Plants must use NO3− to carry out nitrogen fixation.
E) The N2 molecule is too large to enter the stomata.