Read this excerpt from Chapter II of Alice in Wonderland. Her foot slipped, and in another moment, splash! she was up to her chin in salt-water. Her first idea was that she had somehow fallen into the sea. However, she soon made out that she was in the pool of tears which she had wept when she was nine feet high.

Just then she heard something splashing about in the pool a little way off, and she swam nearer to see what it was: she soon made out that it was only a mouse that had slipped in like herself.

Which detail from the excerpt tells the reader that the pool is made up of Alice's tears?

she swam nearer to see what it was
she heard something splashing about
Her foot slipped, and in another moment, splash!
she was up to her chin in salt-water