The sum of three consecutive natural numbers is always divisible by `"____"`.

Options

A. 3
B. 9
C. 15
D. 21

Answer

To solve the problem, we need to find the sum of three consecutive natural numbers and determine what this sum is always divisible by.

### Step-by-Step Solution:

1. **Define the three consecutive natural numbers**:
Let the three consecutive natural numbers be \( x \), \( x + 1 \), and \( x + 2 \).

2. **Calculate the sum of these numbers**:
\[ \text{Sum} = x + (x + 1) + (x + 2) \]
Simplifying this, we get:
\[ \text{Sum} = x + x + 1 + x + 2 = 3x + 3 \]

3. **Factor the sum**:
We can factor out the common term from the sum:
\[ \text{Sum} = 3(x + 1) \]

4. **Determine divisibility**:
From the factored form \( 3(x + 1) \), we can see that the sum is clearly divisible by 3, regardless of the value of \( x \).

5. **Conclusion**:
Therefore, the sum of three consecutive natural numbers is always divisible by **3**.

### Final Answer:
The sum of three consecutive natural numbers is always divisible by **3**.