What declarations can be used to define a data structure holding fields with data elements s_carr_id and s_carrname?

The choice that correctly defines a data structure holding fields with the specified data elements is indeed the one that uses the data declaration syntax. In ABAP, using the syntax "DATA: BEGIN OF" allows you to define a structured type with several fields, enabling the creation of an internal table or a complex data structure.

When you declare a data structure this way, you set up a named structure where you can then define individual fields, like s_carr_id and s_carrname, that will hold the respective data. This syntax is straightforward, making it easy to define multiple fields under a single data structure.

Other options, while they might resemble correct declarations, either lack the appropriate context or are not formatted in a way that allows for the instantiation of a structure. Thus, "DATA: BEGIN OF gs_flight" is the proper choice as it directly relates to declaring a data structure that can have multiple fields.