Based on the analogy given, find the missing number from the given options.
11:13 ::17: …….
A. 29
B. 21
C. 19
D. 23

Options

A. B
B. C
C. D
D. A

Answer

To solve the analogy problem 11:13 :: 17:?, we need to identify the relationship between the first pair of numbers (11 and 13) and apply the same relationship to the second pair (17 and the missing number).

### Step-by-Step Solution:

1. **Identify the relationship in the first pair (11:13)**:
- The first number is 11.
- The second number is 13.
- The difference between 11 and 13 is:
\[ 13 - 11 = 2 \]

2. **Apply the same relationship to the second pair (17:?)**:
- The first number in the second pair is 17.
- To find the missing number, we add the same difference (2) to 17:
\[ 17 + 2 = 19 \]

3. **Conclusion**:
- The missing number that corresponds to 17 is 19.

Thus, the answer is **C. 19**.