The `str.isdigit()` method returns `True` if all characters in the string are digits. This is the most direct and Pythonic way to check if a string can be safely converted to an integer, as it handles the check in a single, readable method call.

The loop iterates `i` from 0 to 4. For even `i` (0, 2, 4), it adds `i` to result. For odd `i` (1, 3), it subtracts `i`. So: 0 + 0 = 0; 0 – 1 = -1; -1 + 2 = 1; 1 – 3 = -2; -2 + 4 = 2. The correct result is 2, which is not listed. There is an error in the provided options. The correct logic yields 2. Given the options, 6 is incorrect. The correct calculation based on the code is 2. Since 2 is not an option, there is a discrepancy. The intended correct answer from the options provided is likely based on a mis-calculation, but following the code exactly gives 2. For the purpose of this test, the closest correct logic from a common mistake would be if it only added evens: 0+2+4=6. However, the correct answer per the code is 2.

The issue is in the line `message = ‘Hello, ‘ + ‘name’ + ‘!’`. Here, `’name’` is a string literal, not the variable `name`. To use the variable’s value, it should not be enclosed in quotes: `message = ‘Hello, ‘ + name + ‘!’`.

Option 1 correctly converts the string to a float, performs the arithmetic, and uses an f-string with a format specifier (`:.1f`) to display the number with one decimal place. This is efficient and Pythonic.

The condition `(x > 5 and x < 10)` is `True` only when `x` is between 5 and 10 (exclusive). The `not` operator inverts this. Therefore, the whole expression is `True` for any `x` that is NOT between 5 and 10. Both 12 and 5 satisfy this (5 is not greater than 5, so the inner condition is False, and `not False` is True).

The fundamental difference is mutability. Lists are mutable (can be modified after creation), while tuples are immutable (cannot be modified). This immutability makes tuples hashable, allowing them to be used as keys in dictionaries, and signals that the collection is fixed.

The `.get()` method for dictionaries allows a second argument, which is a default value. If the specified key (‘status’) is not found in the dictionary, the method returns this default value (‘N/A’) instead of raising a `KeyError`.

The outer loop runs for i = 1, 2, 3. For each `i`, the inner loop runs for j = ‘a’, then j = ‘b’. It appends a tuple `(i, j)` to the list in that nested order. Therefore, the sequence is (1,’a’), (1,’b’), (2,’a’), (2,’b’), (3,’a’), (3,’b’).

A `try-except` block is the standard Python idiom for handling potential errors (exceptions) gracefully. You would place the file-opening code in the `try` block and the error message in an `except FileNotFoundError` block. This prevents the program from crashing and allows for controlled error handling.

The `str.isdigit()` method returns `True` if all characters in the string are digits. This is the most direct and Pythonic way to check if a string can be safely converted to an integer, as it handles the check in a single, readable method call.0