You take the mass of the empty detergent container and find that is 390 g. it’s volume is 300.0ml what it’s density

Ibelieve your answer is true 

It is a mixture. simply put, a compound must be pure, that is, of only one chemical structure and composition. a mixture is made of different chemical substances (i.e. elements, molecules, compounds) that are not chemically bonded to each other, but instead physically grouped together, as in the case of gasoline (a homogeneous solution).

Ithink the answer is c