Which of the enzymes are not present in mitochondria?

In heme synthesis, the first three enzymes (ALA synthase, ALA dehydratase, and porphobilinogen deaminase) are cytosolic, while the later enzymes (including coproporphyrinogen oxidase, protoporphyrinogen oxidase, and ferrochelatase) are mitochondrial. ALA dehydratase (also known as porphobilinogen synthase) catalyzes the condensation of two ALA molecules to form porphobilinogen in the cytosol, making it the correct answer.