The correct option is A 100
When a decimal is multiplied by 10, 100, 1000 etc, the decimal point gets shifted to the right based on the number of zeros.
Here,
12.34 x 10 = 123.4
12.34 x 100 = 1234
12.34 x 1000 = 12340
∴ If we multiply 12.34 by 100 we get 1234.