can i get the answer to B tree diagram?

(1)A class in probability theory consists of 6 men and 4 women. An exam is given and the students are ranked according to their performance knowing their gender but without knowing their names. Assuming that students obtains a different score (i.e. no two students will obtain the same score). (a) How many different rankings are possible? (b) If only 3 students are selected at random, how many different rankings are possible in this case? Use a tree diagram to nd the list of all possible rankings in this case