Which of the following explains the unique mechanism by which $\delta$ -aminolevulinic acid is synthesized in most bacteria,archaea and plants?

A)glutamic acid is attached to its tRNA and then reduced to glutamate-1-semialdehyde
B)glutamic acid undergoes reduction and cyclization to $\Delta$ ¹-pyrroline-5-carboxylate
C)glutamic acid undergoes carboxylation to $\gamma$ -carboxyglutamic acid
D)glutamic acid condenses with itself via the $\delta$ -carboxyl and amine group
E)none of the above