When you find the gram formula mass, the results should be in *
Help me out ;/

 g/mol

Explanation:

The gram formula mass of  CuSO 4  is  159.60 g/mol  

Multiply the subscript for each element by its molar mass (atomic mass on periodic table in g/mol). Then add the results. This will give you the molar mass of the compound (mass of 1 mole).

Cu : ( 1 × 63.546 g/mol )   = 63.546 g/mol

S : ( 1 × 32.065 g/mol )      = 32.06 g/mol

O : ( 4× 15.999 g/mol )     =  63.996 g/mol

CuSO 4 :  63.546 g/mol  +  32.06 g/mol  + 63.996 g/mol  = 159.60 g/mol  (rounded to two decimal places)

the answer is definitely c.