The correct answer is C. sonnet.
The prologue to Act I of Romeo and Juliet is written in the form of a sonnet (a Shakespearean sonnet, to be more precise). A sonnet is a poem which consists of 14 lines. When it comes to Shakespearean sonnet, its form is a bit different than other sonnets. These 14 lines are divided like this - the first twelve lives are divided into 3 quatrains (a quatrain contains 4 lines), and the final two lines are called a couplet and they contain the main message of the sonnet.
