Which of the following are acceptable module names?

The selection of "main_module" as an acceptable module name is grounded in the naming conventions established by Puppet. According to these conventions, module names must follow specific criteria, which include starting with a lowercase letter and allowing the use of letters, numbers, and underscores.

"main_module" adheres to these guidelines, beginning with "main," a lowercase letter, and properly incorporating an underscore to separate the two parts of the name. This structure enhances readability while still complying with Puppet's requirements for module names.

In contrast, "14module" does not meet the criteria because it starts with a number, which is not permitted. "module14" is valid as it starts with a letter and includes numbers; however, when considering typical naming conventions, it might be less clear than "main_module." "main" is also an acceptable name as it starts with a letter and consists of only a single word, but it may lack specificity depending on the context of usage compared to "main_module."

Overall, "main_module" stands out as the most fitting option aligned with best practices and conventions in Puppet module naming.