Forensic research can be tedious and sometimes gruesome. But police and investigators "need more types of evidence," says Gilbert. To piece together the truth about a crime, they need all the scientific tools they can get. How do the words tedious and gruesome contribute to the meaning of this passage?

A. They express the difficulties that forensic researchers experience as they search for evidence.
B. They suggest that forensic research is a boring line of work.
C. They explain how important forensic research is to the future of solving crimes.
D. They show how different forensic researchers and police officers are.