Vertical columns on the periodic table are known as and horizontal rows are called
O periods, groups
groups, periods
O metals, nonmetals
O metalloids, metals

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).

The answer is c - the principal of original lateral continuity.