Examine this chemical structure.

From the list below, select ALL of the functional groups present in this structure. Note that

there may be more than one correct response to this question, and you must select all of the

correct responses to receive full credit. Selecting incorrect answers will deduct from your

mark. The lowest mark you can receive for the question as a whole is $0.$

a$.$ Carbonyl $$

b$.$ Phosphate $x$

c$.$ Hydroxyl $$

d$.$ Amino

e$.$ Sulfhydryl

f$.$ Carboxyl