When someone refers to the "periods" of the periodic table, what are they referring to?

A. the metalloids B. the rows of the table C. the different historical models of the table D. the groups of elements with similar properties

When someone refers to the "periods" of the periodic table, what are they referring to?

A period in the periodic table is a horizontal row ... Each next element in a period has one more proton and is less metallic than its predecessor. Arranged this way, groups of elements in the same column have similar chemical and physical properties, reflecting the periodic law.

So the closest answer would be B