b.a rhymed couplet
Shakespearean sonnets have a very specific rhyme scheme. The rhyme scheme is ABAB CDCD EFEF GG. The final two lines rhyme and can be found in the own stanza sometimes. This rhyming couplet often provides a resolution to the ideas developed in the rest of the sonnet. Shakespeare doesn't restrict his sonnet form to just his sonnets. He also uses them in his plays. For example, Romeo and Juliet's first conversation is written in the form of a sonnet.