You ___ get a visa before you go abroad next summer ?

The phrase "You ___ get a visa before you go abroad next summer" requires a modal verb that conveys obligation or necessity. Among the given options, "will have to" is the most fitting choice because it indicates a future requirement. When someone is planning to travel abroad, obtaining a visa is often a mandatory step, depending on the destination, making it necessary to express that obligation clearly.

Let's examine the other options:

- A) may suggests permission or possibility but does not convey obligation.
- B) can indicates ability but lacks the sense of requirement that the context necessitates.
- C) could implies a past ability or a more conditional sense, which again does not fit the obligatory context.

In contrast, "will have to" directly communicates that obtaining a visa is not just recommended but required before the upcoming trip. This future implication aligns with the context of planning for summer travel, making "will have to" the correct choice. It underscores that without a visa, the individual will not be able to legally enter their destination, emphasizing the necessity of obtaining the visa beforehand.