Which of the Below Statements Is TRUE

Which of the below statements is TRUE?

A) Fixed-rate securities are attractive to some institutional investors because they allow them to buy an asset with an income stream that closely matches the floating nature of the income of some of their liabilities.
B) The lowest-grade bonds are designated by Moody's by the symbol Aaa and by the other three rating systems by the symbol AAA.
C) Frequently, the ability of an issuer to make interest and principal payments is seriously and unexpectedly changed by a natural or industrial accident or some regulatory change.
D) Each rating agency periodically publishes a table showing the upgrade and downgrade history of the issues that it rated.