Answer: Option C

Explanation:
Let X be a discrete random variable that counts the number of siblings a randomly selected student has. Then the expected value of X is defined as:

Where
is the probability that a randomly selected student has
siblings
With

So in this case we know that
#of siblings 0 1 2 3 4 5
probability 0.20 0.65 0.08 0.04 0.02 0.01
Therefore:



The answer is the option C.