It's got to be C because none of the others relate to collaboration, but I'd say if you were unsure about this answer then the only other sensible one could be B, but I'd go with C.
Answer:
confidentiality: This mean a private stuff or a private document
Expert witnessing: This means a professional seeing something directly
Engineers' approach to risk: This means an Engineer going to a dangerous place
<span>The sentence with an indirect object is: After she scored the exams, Ms. Dieken gave the students their grades. </span>
