$$15=1+2+3+4+5$$. 
Eddie reads at least one chapter of a $$15-$$chapter book each day. If he is asked to read a different number of chapters each day, this book can be read for at most~\uline{~~~~~~~~~~}~days. 

  - $$3$$ 
  - $$5$$ 
  - $$12$$ 
  - $$15$$ 