Correct Answer - c

The effective length of the simple pendulum

= Length of the string + radius of the bob

`=102.6cm+(2.56)/(2)cm`

`therefore L=102.6+1.28=103.88cm`

But in addition and subtraction, the result should have the minimum number of decimal places, which are present in the added quantities. In this case, 102.6 cm has only one decimal figure.

`therefore` The effective length of the simple pendulum, by using correct number of significant figures is 103.8 cm.

[Note : If we use rounding off method, then the answer will be 103.9.]

[0.88 is rounded off to 0.9]