quantization level (i.e. coding level) = starting level of a paragraph+quantization level number of codes in a paragraph * quantization interval.

In this question, the paragraph code C2C3C4=111, that is, the sample value falls in the eighth paragraph, and the starting level of the eighth paragraph is 124, and the quantization interval is 64.

the code in the segment C5C6C7C8=11, that is, the serial number of the sample in the fourth segment is 5. (If there are tables in these books, just look them up yourself)

So IC = 124+5 * 64 = 1344.

(It may not be calculated correctly, but it is such a thought process)