Which of the Following Is NOT One of the Four

Which of the following is NOT one of the four characteristics of IPOs that puzzle financial economists?

A) The costs of the IPO are very high, and it is unclear why firms willingly incur such high costs.
B) The long-run performance of a newly public company (three to five years from the date of issue) is superior to the overall market return.
C) On average, IPOs appear to be underpriced.
D) The number of issues is highly cyclical.