Why Is It Difficult to Measure Human Rights Abuses

Why is it difficult to measure human rights abuses?

A) States lack sufficient resources to report on their level of respect for rights.
B) The only organizations that release annual reports on respect for human rights are usually biased.
C) There are few international nongovernmental organizations that work to track human rights abuses.
D) Governments carry out some abuses of human rights in private,making it difficult to find evidence of abuses.