Four of the following belongs to a group in a certain way, find which of the one does not belong to that group?

Study the following information carefully to answer the given question: Eight students M, N, O, P, Q, R, S and T appear in an examination in two different shifts either at 8AM or 12PM. They give exam on different months of the same year starting from July to October. Only three persons give exam in between T and Q, whose exam is in the month which have odd number of days. M gives exam in the month having 30 days. P gives exam in morning but after T. Four persons give exam between R and O. T gives exam after Q. S gives an exam in afternoon shift of the month which has odd number of days but before T. R gives the exam in the month having 31days but not in October. Only one person gives exam between M and N