if probability of success is 0.5%,then the probability of failure is:

(a)0.95 (b)0.095 (c)99.5 (d)0.995

plz explain the answer

Probability of success = 0.5 % 

now, probability of success + probability of failure = 100 %

 so, probability of failure = (100 - 0.5)% = 99.5 % = 99.5 / 100 = 0.995