Find the missing number?

5
9
6
3

The answer is 6.

The missing number is the sum of the two numbers on either side of it. In this case, the two numbers on either side of 6 are 5 and 9. Therefore, the missing number is 6.

A. 5 is not the missing number because it is not the sum of the two numbers on either side of it.
B. 9 is not the missing number because it is not the sum of the two numbers on either side of it.
C. 6 is the missing number because it is the sum of the two numbers on either side of it.
D. 3 is not the missing number because it is not the sum of the two numbers on either side of it.