In Kotlin, how do you declare a variable whose value cannot be changed after initialization?

The correct option is:

• Using the val keyword

In Kotlin, the val keyword is used to declare a read-only variable (also known as an immutable variable). Once a val variable is initialized, its value cannot be changed or reassigned. The example val pi = 3.14 correctly demonstrates this, stating that 'pi' cannot be reassigned.

The var keyword is used for mutable variables, allowing reassignment. The let keyword is a scope function, and const is used for compile-time constants, which are a specific type of immutable variable.