The probability that a 20-year-old female will survive the next year is 0.999544. An insurance company takes a random sample of 50 females who are 20 years old. Let X be the number of people in the sample who are still alive 1 year later.

a. Find the probability that exactly 49 survive.
b. Find the probability that the number who survive is between 40 and 48, inclusive.
c. Find the probability that at least one person will not survive.
d. Find the expected number who will survive.