Select the most appropriate meaning of the underlined idiom.

The mother-in-law deliberately rained on the new bride’s parade when she asked her to change the dress of her choice.

To spoil a moment

The most appropriate meaning of the underlined idiom is (3) To spoil a moment.

The other options do not fit the context of the sentence.

• To force traditions upon someone is to make them follow a certain set of customs or beliefs, even if they don't want to.
• To make someone tearful out of viciousness is to intentionally hurt someone's feelings and make them cry.
• To save one from embarrassment is to prevent someone from feeling ashamed or humiliated.

The idiom "rain on someone's parade" means to spoil someone's happiness or excitement. In this case, the mother-in-law is spoiling the new bride's happiness by asking her to change the dress of her choice.