A number is selected at random from the set {2, 3, 4, ... 10}. Which event, by definition, covers the entire sample space of this experiment?

a. The number is greater than 2.

b. The number is not divisible by 5.

c. The number is even or less than 12.

d. The number is neither prime nor composite.

e. The square root of the number is less than 3.

Let's do process of elimination

a) 2 is part of the set and 2 is not greater than 2. NO

b) 5 and 10 in the set are divisible by 5. NO

c) 2,4,6,8,10 are even but the rest are odd (BUT note the word "or"). the rest are less than 12. YES

d) 0 and 1 are the only numbers that are neither prime nor composite (they're not even part of the set). NO

e) the square root of 9 is 3 so the maximum number is 9 (but what happened to 10?) NO