Some questions are solved on the basis of a certain system. On the same basis, find out the correct answer from amongst the four alternatives for the unsolved equation in each question.
`11xx12xx13=234,24xx23xx35=658,31xx43xx54=?`

Options

A. (a) 497
B. (b) 974
C. (c) 749
D. (d) 479

Explanation

To solve the equation \(31 \times 43 \times 54\) based on the pattern established in the previous examples, we will follow the same method used for the earlier equations.

### Step-by-Step Solution:

1. **Identify the numbers in the equation**: We have \(31\), \(43\), and \(54\).

2. **Add the digits of the first number (31)**:
- \(3 + 1 = 4\)

3. **Add the digits of the second number (43)**:
- \(4 + 3 = 7\)

4. **Add the digits of the third number (54)**:
- \(5 + 4 = 9\)

5. **Combine the results**:
- The results from the additions are \(4\), \(7\), and \(9\).
- Therefore, we can write the final answer as \(479\).

### Final Answer:
The answer to the equation \(31 \times 43 \times 54\) is \(479\).