Question: What restriction is there on the type of `var` to compile this `i := myVal.(int)?`

1. `myVal` must be an integer type, such as `int`, `int64`, `int32`, etc.
2. `myVal` must be able to be asserted as an `int`.
3. `myVal` must be an interface.
4. `myVal` must be a numeric type, such as `float64` or `int64`.

Answer: The correct answer of the above question is Option C:`myVal` must be an interface.