Conversion of decimal number 9910 to it’s octal number equivalent is A. 1218 B. 1438 C. 1248 D. 1198 E. None of the above

The correct answer is $\boxed{\text{C) 1248}}$.

To convert a decimal number to octal, you divide the decimal number by 8 repeatedly, and write down the remainders in reverse order.

For example, to convert 99 to octal:

$$99 \div 8 = 12 \text{ R } 3$$
$$12 \div 8 = 1 \text{ R } 4$$
$$1 \div 8 = 0 \text{ R } 1$$

So, the octal equivalent of 99 is $124_8$.

In this case, 9910 is equivalent to $1248_8$.

Option A is incorrect because $1218_8$ is not equal to 9910.

Option B is incorrect because $1438_8$ is not equal to 9910.

Option D is incorrect because $1198_8$ is not equal to 9910.

Option E is incorrect because $\boxed{\text{C) 1248}}$ is the only option that is equal to 9910.