I choose randomly choose 9 students from the class to write the answers to the homework problems on the board. If 20% of the students in the class did not complete the homework, find the probability of each of the following events. Show all relevant work.

(a)All of the 9 students have completed the homework.

(b)The first student did not complete the homework but the rest did.

(c)Exactly one of the 9 students has completed the homework.