Final answer:
In C programming, single-line comments start with //, and multi-line comments start with /* and end with */. These comment syntaxes enable the documentation of code within the source files.
Step-by-step explanation:
The question pertains to the syntax used for creating comments in the C programming language. In C, comments can be made in two ways. Single-line comments begin with //, whereas multi-line comments begin with /* and end with */. Therefore, the statement that C comments can include multiple lines is true if they start with /* and end with */.