What happens if you type nothing (no text) in the search text field and press Enter? A: The hitlist will show all terms of the selected source language by default. B: An error message will be displayed (you cannot perform a search when the search text field is empty). C: The first 25 hit terms will be shown in the hitlist by default. D: The hitlist will be empty.

信息中介和专门做数据挖掘的代表性公司有（） A: SASInstitute B: NetTracker C: WebTrends D: HitList