Answer: B) abbcb.
Step-by-step explanation: To determine the rhyme scheme of a poem or stanza, we must pay attention to the final sound of each line. The similar sounds will have the same letter, and the unique sounds, different letters (starting with the letter "A"). In the given poem, the first line ends with the word "exhibit" and it is an unique sound, so it will have the letter A, the lines 2, 3 and 5 end with the words "again," "plain," and "vain" which have the same sound, so they will have the letter "B" and the line 4 has also an unique ending sound ("bake") so it will have the letter "C" the complete rhyme scheme would be: abbcb.