问题如下：
4. The most appropriate response to Madison’s question regarding the spread measure is the:
选项：
A. Z-spread.
B. Treasury-Eurodollar (TED) spread.
C. Libor-OIS (overnight indexed swap) spread.
解释：
B is correct.
The TED spread, calculated as the difference between Libor and the yield on a T-bill of matching maturity, is an indicator of perceived credit risk in the general economy. An increase (decrease) in the TED spread signals that lenders believe the risk of default on interbank loans is increasing (decreasing). Therefore, the TED spread can be thought of as a measure of counterparty risk.
z spread 反应的不是 全经济的？ 视频课里说这个spread是以 国债为 benchmark 的 所以a答案为什么不行呢？
