B. Where did Mia find the box with colours and brushes? 1) In her room. 2) In her grandmother's room. 3) In the attic.

3) In the attic. Объяснение: В тексте сказано: "One sunny afternoon she was doing the cleaning in the attic of her old house. Suddenly she found a dusty box.", что означает, что Мия нашла коробку на чердаке.