The correct answer is: C. used value
The used value is the result of taking the computed value and completing any remaining calculations to make it the absolute theoretical value used in the layout of the document.
The computed value is the value that is calculated based on the declared value and any other relevant settings. For example, if the declared value is 10px and the font size is 12px, the computed value will be 120px.
The used value is the value that is actually used in the layout of the document. It may be different from the computed value if there are any other relevant settings that affect the value. For example, if the font size is set to “auto”, the used value will be the value that is calculated based on the font size of the surrounding text.
The cascaded value is the value that is used in the layout of the document if there are multiple declarations for the same property. It is calculated by taking the computed value of the first declaration and then cascading down the document, taking the computed value of each subsequent declaration and applying any relevant inheritance rules.
The declared value is the value that is specified in the CSS code. It is the value that is used to calculate the computed value.
None of the mentioned is not the correct answer.