The is located under the forebrain and midbrain.
a. forebrain
b. midbrain
c. hindbrain
d. brainstem

For anyone who still needs this the answer is C. hindbrain

Just had this on my test review, hope this helps :)

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products