I got option [a] for this problem, just would like to have my answer double-checked, thanks for any assistance

Q: The number of red blood cells per square unit visible under a microscope follows a Poisson distribution with a mean of 4. Find the probability that more than 5 such blood cells are visible to the observer.

a) 0.2149

b) 0.7851

c) 0.3712

d) 0.6288

e) none of the above