For two events, e and f, p(e) = 0.7, p(f) = 0.4 and p(e ∩ f) = 0.1. which statement is true?
a. the events e and f are pairwise disjoint events.
b. the events e and f are independent events.
c. either e occurs or f occurs all the time.
d. the events e and f are both pairwise disjoint and independent events.
e. none of these are true.