I believe the answer is b.
I think it is a drug-resistant bacteria.
Answer: aa bb cc dd
Explanation:
<em>To identify the rhyme scheme, we look to see the lines where the last word of the lines rhymes. If we label the first line 'a', then all lines that end with the same rhyme as the first would also be 'a'. We then do this for all the lines.</em>
...The crown upon your brows may flourish long, <u><em>a</em></u>
<u><em></em></u>
And that your arm may in your God be strong! <u>a </u>
O may your sceptre num'rous nations sway, <u><em>b</em></u>
And all with love and readiness obey! <u><em>b</em></u>
But how shall we the British king reward! <u><em>c</em></u>
Rule thou in peace, and our lord! <u><em>c</em></u>
Midst the remembrance of thy favours past, <u><em>d</em></u>
The meanest peasants most admire the last... <u><em>d</em></u>
