Seven students A, B, C, D, E, F, and G are to give speeches to the class. The order of speaking is determined by random selection.
a) Find the probability that E will speck first.
b) Find the probability that C will speak fifth and B will speak last.
c) Find the probability that the students will speak in the following order: G, D, E, C, A, B, F
d) Find the probability that A or B will speak first.