The correct answer is Petrarchan (or Italian) sonnet. It is structurally divided into two stanzas, an 8-line stanza (an octave), and a 6-line stanza (sestet). Even the rhyme supports this structural division: the octave usually has the ABBAABBA rhyme pattern, while the rhyme pattern of the sestet may vary (the most typical arrangements being CDECDE or CDCDCD).