The First Reaction Which Is Unique to the Isoprenoid Biosynthetic

The first reaction which is unique to the isoprenoid biosynthetic pathway is

A) 2 acetyl-CoA --> acetoacetyl-CoA in the mitochondria.
B) acetoacetyl-CoA + carnitine --> acetoacetyl-carnitine + CoA at the inner mitochondrial membrane.
C) acetoacetyl-CoA ---> beta-hydroxybutyryl-CoA in the cytosol.
D) acetoacetyl-CoA + acetyl-CoA --> HMG-CoA + CoA in the mitochondria.
E) HMG-CoA + 2 NADPH --> mevalonic acid + 2 NADP + CoA in the endoplasmic reticulum.