One of the basic requirements of probability is ________.

Note:P(Ac) in the multiple choice answer = P(Ac)

Group of answer choices

P(A) = P(Ac) 1

both P(A) = P(Ac) 1 and if there are k experimental outcomes, then P(E1) + P(E2) + ... + P(Ek) = 1

for each experimental outcome Ei, we must have P(Ei) 1

if there are k experimental outcomes, then P(E1) + P(E2) + ... + P(Ek) = 1