Answer:
Option B - 0.15
Explanation:
Given : The probability of success in a binomial event is 0.85.
To find : What is the probability of failure?
Solution :
The probability of event is always 1.
i.e., sum of probability of success and failure is 1
The probability of success in a binomial event is P(S)=0.85.




Therefore, Option B is correct.
The probability of failure is 0.15.