The answer is $\boxed{8 13 20}$.
In the pyramid number, the first number is the sum of the two numbers below it, and the third number is the sum of the two numbers above it. So, the answer is the number that, when added to the two numbers below it, gives 9, and when added to the two numbers above it, gives 21. The only number that satisfies this condition is 8.
Option A: 2 7 14. This is not a valid pyramid number because the first number is not the sum of the two numbers below it.
Option B: 8 13 20. This is a valid pyramid number because the first number is the sum of the two numbers below it, and the third number is the sum of the two numbers above it.
Option C: 6 15 18. This is not a valid pyramid number because the third number is not the sum of the two numbers above it.
Option D: 10 23 30. This is not a valid pyramid number because the first number is not the sum of the two numbers below it.
