字母Aa-Dd的认读与书写 — 英语阅读题

Read the short passage and answer the question. Hello! My name is Alice. I am a new student. I like letters very much. The first letter of my name is A. I have three good friends. Ben's name starts with B. Cathy's name starts with C. David's name starts with D. We make a fun game: we say the letters in ABC order and clap our hands. Cathy says her letter is between B and D. David says his letter is the last one of the four. Alice, Ben, Cathy and David are happy together in the school. Question: Which letter comes just before D in the four letters (A, B, C, D)? Write its small letter (小写形式).