Adding -s is the most common. for example: books, cups, pencils, etc. -es might have been the one that confused you, but that isn't a super common ending for plurals--instead, a more common one would be "-ies" which is when you drop the y (berry becomes berries, for example).
Answer: C. Throw the poisoned entrails into the cauldron.
Explanation:
The three witches (or<em> 'weird sisters'</em>) are supernatural creatures from Shakespeare's <em>Macbeth</em>. They make a prophecy about Macbeth's future at the beginning of the play, predicting that Macbeth would become a king.
In <em>Act IV, Scene I</em>, the witches are dancing around the cauldron and adding some ingredients into it - poisoned entrails, wolf's tooth, a frog's tongue, etc. They are preparing a strange potion. After the potion is finished, Macbeth enters the stage, determined to find out the truth about the witches' prophecies.