The following data gives the marks obtained by 40 students in a class. Arrange these marks in a table using tally marks. 6, 7, 4, 11, 12, 10, 12, 9, 4, 3, 10, 12, 7, 6, 4, 5, 3, 2, 4, 11, 4, 3, 8, 4, 2, 10, 11, 9, 8, 6, 9, 8, 9, 5, 4, 12, 10, 9, 6.

a. How many students scored mark more than or equal to 10 ?
b. How many students scored marks below 5? c. How many students scored 9 marks?​