What is the name of the Travis CI configuration file?

The configuration file for Travis CI is named ".travis.yml". This file is essential for defining the build instructions for your project, including language specifications, environment variables, build scripts, and various settings related to the continuous integration process. The presence of the leading dot in the filename indicates that it is a hidden file in Unix-like systems, which is a standard convention for many configuration files.

By using ".travis.yml", Travis CI recognizes that it should read and execute the configuration provided within this file to determine how to build and test the software. Moreover, this file must be located in the root directory of the repository in order for Travis to locate and use it effectively during the continuous integration process.

The other options listed, while they may look similar, do not align with the standard naming convention employed by Travis CI and therefore would not be recognized by its systems.