Which of the Following Explains the Unique Mechanism by Which $\delta$

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 $\sigma$ -carboxyl and amine group
E) none of the above