In this case, please select the plural form according to the actual meaning.

1. When using "how much" to ask about the price of an item, the singular form is usually used. For example: "How much is the book?" In this sentence, "is" is in the singular form, matching "the book."

2. If you ask for the total price of multiple items, you can use the plural form. For example: "How much are these three books?" In this sentence, "are" is in the plural form, matching "these three books."