The average of the four numbers is 8. This gives the sum of all the four numbers as 8*4 = 32.

As the sum of three of the numbers is 22, the fourth number is 32 - 22 = 10.

**The correct answer is option d.**

The average of the four numbers is 8. This gives the sum of all the four numbers as 8*4 = 32.

As the sum of three of the numbers is 22, the fourth number is 32 - 22 = 10.

**The correct answer is option d.**