The correct option is C 8.15%
Let actual sides of the rectangle are 'l' and 'b' respectively.
The measured sides are (l+0.05l) and (b+0.03b) i.e. 1.05l and 1.03b
Therefore, Measured area =(1.05l)(1.03b)
Actual area =lb
Error in area =1.0815lb−lb=0.0815lb
∴% error=0.0815lblb×100%=8.15%