The blood groups of 30 students of class IX are recorded as follows: A    B       O    O    AB    O    A    O       B       A    O    B      A    O    O A    AB    O    A    A      O    O    AB       B       A    O    B      A    B     O A student is selected at random from the class from blood donation. Find the probability that the blood group of the student chosen is: (i)               A       (ii)   B      (iii)   AB          (iv)     O