Answer :

To solve the problem of determining what will be seen on the next line after executing the command `int("3.9")`, let’s analyze the situation step-by-step:

1. Understanding the `int` Function: The `int` function is used to convert a value to an integer. It can take a string or a number as its argument and then return an integer representation of it.

2. The Input Given: The argument provided to the `int` function in this case is the string `"3.9"`.

3. Valid Integer String: For the `int` function to successfully convert a string, the string must represent a valid integer value. Valid integer strings include strings like `"1"`, `"23"`, or `"100"`.

4. Checking the Argument: The string `"3.9"` represents a floating-point number, not an integer. This means that `"3.9"` is not a valid integer string and cannot be directly converted to an integer using the `int` function.

5. Result of the Conversion Attempt: Attempting to convert a non-integer string with `int` will result in an error because the function expects the string to represent an integer.

Therefore, given that the argument does not meet the criteria for a valid integer string, the appropriate output will be an error.

The selection corresponding to this situation is:
- an error statement

So, the correct answer to the multiple-choice question is:
```
an error statement
```