Fill in the blank with the correct Modal out of the given options.

Urvashi's sister certainly ________ disapproved the tone of her sister took to address the househelp.

would have

The correct modal to fill in the blank is: would have

Here's why the other options are not suitable:

• could have: This implies possibility, but the sentence suggests certainty about Urvashi's sister's disapproval.
• will have: This refers to the future, while the sentence talks about a past event.
• would be: This suggests a hypothetical situation, but the sentence expresses a definitive opinion held in the past.

Therefore, "would have" accurately conveys the past certainty of Urvashi's sister's disapproval regarding the tone used towards the househelp. It indicates that disapproval would have been her reaction if she had witnessed the scene.