Which sentence has an error? A) Whose name is written on these checks that were given to our cashier at lunch today? B) Do not underestimate your ability to learn a new skill, no matter what age you may be. Eliminate C) At the beach with her two sisters, John's mother wasn't sure whether those flip-flops were hers' or one of theirs. D) Some of the other students turned in essays half-done, but mine had already been through two drafts and strong edits.