Replace x and y with the correct module to generate the following output. Calculation done on: *actual date* 36.0

The correct choice involves the use of the 'math' module and the 'datetime' module. The 'math' module provides access to mathematical functions and constants, which would be essential for performing calculations leading to a numerical output, such as 36.0. Functions like square root, exponential, or others could be used here depending on the calculation needed.

On the other hand, the 'datetime' module is necessary for working with dates and times. It allows for the retrieval of the current date and time, which is crucial for generating an output that refers specifically to "calculation done on: actual date". This module can be used to get today's date in various formats, facilitating the desired output message.

In this case, the combination of these two modules—math for the computation and datetime for the current date—is what leads to the expected result of the output format. Other options either lack the necessary mathematical capabilities or do not include a component for handling dates and times effectively.