Answer: Option 'A' is correct.
Step-by-step explanation:
In the binomial probability formula, we have
[tex]P(X=x)=^nC_xp^{x}q^{n-x}[/tex]
Here, n = number of events
x = number of trials
p = probability of success
q = probability of failure
x is the number of trials among which we decide the number of successes and number of failures.
So, Option 'A' is correct.