Answer
(a) equal to
(b) option (I)
Work Step by Step
(a) We know that the wood rises to the surface and floats while all the parameters remain the same and hence the reading on the scale is equal to the previous reading.
(b) We know that the best explanation is option (I) -- that is, the same mass is supported by the scale before and after the string breaks, and therefore the reading on the scale remains the same.
