Answer:
C) banks falsely reporting the interest rates they offered in the interbank market.
Step-by-step explanation:
The LIBOR rate is used all over the world to set banking interest rates. it reflects the cost of interbank loans. The LIBOR was used as a benchmark to charge interest rates to clients around the world, e.g. LIBOR + 2%.
The scandal involved many major banks, e.g. Deutsche Bank, Barclays, UBS, Rabobank, HSBC, Bank of America, Citigroup, JPMorgan Chase, the Bank of Tokyo Mitsubishi, Credit Suisse, Lloyds, WestLB, Royal Bank of Scotland, and a long list of etc.
What the banks did was artificially manipulate the LIBOR rate by increasing or decreasing it to show artificial profits from trading activities. When the manipulation was discovered, it had been going on for at least 7 years, and some believe it started earlier.