calculating the number of mole of COSO4 reacted
=mass/R.F.M
R.F.M of CUSO4 is 63.54+32+64=159.6
moles is therefore 200g/159.54=1.254moles
since reacting ratio is 1:1 ,moles of Cu is also 1.254moles
mass is therefore moles x R.F.M
1.254x63.54=79.6g(answer C)