3
0
1
7
Answer is Right!
Answer is Wrong!
The answer is $\boxed{1}$.
The missing number is the number that, when added to the other two numbers, gives the sum of $10$.
The first number is $3$. The second number is $7$. When we add $3$ and $7$, we get $10$. Therefore, the missing number is $1$.
Option A, $3$, is incorrect because $3$ is already one of the numbers in the question.
Option B, $0$, is incorrect because $0$ does not add up to $10$ when added to either of the other two numbers.
Option C, $1$, is correct because $1$ adds up to $10$ when added to either of the other two numbers.
Option D, $7$, is incorrect because $7$ is already one of the numbers in the question.