Mrs. Martin, a third-grade teacher, is instructing cursive writing. At first, she reinforces even crude attempts to reproduce letters with an encouraging word; as time goes on, though, she reinforces only well-formed letters. By reinforcing progressively better attempts at writing letters, Mrs. Martin is using

Answer: Ms. Martin is using a Positive reinforcement, which means giving something (complement, reward) to someone, when they perform the desired action.

Explanation: She is by complementing, encouraging her students to make efforts and try to write better. Therefore, she is able to get that her students, through practicing, reach a better level of hand-writing.