question 5 what functional group is this? carboxyl sodium sulfhydryl

question 5 what functional group is this? carboxyl sodium sulfhydryl
Answer
Brief Explanations:
The highlighted functional group in the molecule is -SH. The -SH group is known as a sulfhydryl group. A carboxyl group is -COOH. Sodium is an element, not a functional - group in this context.
Answer:
C. sulfhydryl