article: When Mr. Brown entered the classroom that Friday morning, he stopped at the blackboard.  For there, on the blackboard, were words in huge red letters: BROWN IS STUPID!
  Mr. Brown thought for a moment. This could only have been the work of one of the four boys who had been kept in after school the day before.
  Mr. Brown turned the blackboard around so that the words could not be seen. Half an hour later,Mr. Brown wrote four names on the board: Gerald, Alex, Michael and Laurie. Then he said, "I want these four to stay in the classroom. The rest of you may go to the playground."
  The four boys came to the blackboard. "One of you has written a most impolite remark on the blackboard," he stared  at them and _ , "which one of you did it?"
  The four boys gathered closer together, afraid of what was to come.
  "Was it you, Gerald?"
  Gerald shook his head. "No, it was not me, Sir," he gave the teacher a most sincere look in his wide eyes.
  "What do you have to say, Alex?"
  "I don't know anything about it, Sir," said Alex, and his ears turned red.
  Michael had a bright idea. "Perhaps someone broke in during the night," he said. "And when he saw the lovely red chalk lying there, he wrote something on the blackboard."
  "Is that the best you can think so, Michael?" asked the teacher.
  "I only thought ..."
  "And what about you, Laurie?"
  Laurie said in a rather low voice, "I didn't do it, Sir. I don't even know what it says on the blackboard."
  "You really don't know what's written there?" Mr. Brown asked. "And I don't think dear Gerald knows either."
  "No, Sir. No idea."
  "Michael, Alex, can either of you tell me what it says on the blackboard?"
  "No, Sir!" the two boys answered together. Brown walked forward and his fingers seized  a schoolboy. He said in his kindest and softest voice to the other three boys, "Very well. I only punish the one who has been telling lies, and you three may go to the playground!"
question: Who has been telling lies?
options: Gerald Alex Michael Laurie