How many candidates take exam between the exam of A and N?

Study the following information carefully to answer the given question: IBPS Exam of Ten candidates have scheduled in five different months viz. January, April, July, October and December, but not necessarily in the same order. The exam will conduct 18th and 28th date of each month and each candidate have exam on different dates. There is four candidate’s exam between the exam of B and N. Only four candidates take exam before the exam of O. There are same number of exam between N and C’s exam as between J and O’s exam. Exam of both B and R falls in the month having 30 days but R’s exam is after B’s exam. There is no exam between the exam of F and
A. The exam date of C and A is not same. The exam month of D and N is same. One of the persons is
M.