Answer:
The answer is indeed the third option: a page at the front of a book that lists units and chapters with their page numbers.
Step-by-step explanation:
I believe the first option would be an index; the second option would be a glossary; and the last one is most likely a preface.
A table of contents is a page or pages, usually before the actual book or work, that lists the chapters or sections to be found in it. It also lists what is included in them, as well as the pages at which they commence. Apparently, the first table of contents ever used was written by Quintus Valerius Soranus, in 82 B.C.